Alaska Volcano Observatory - Redoubt

Redoubt Volcano Latest Observations

The 2009 eruption of Redoubt continues. Seismicity at the volcano has dropped over the past 48 hours, though it remains elevated. This change does not negate the possibility of an explosive eruption over the coming days.

Vigorous steam and gas emissions are visible in web camera images today.

Two AVO field crews are out near the volcano today. A helicopter-supported crew is collecting thermal images of the dome, sampling ash east of the volcano, and sampling lahar deposits in the Drift River. A fixed-wing field crew is collecting gas data from the plume.

AVO is monitoring Redoubt's activity 24/7.

2009-05-08 13:12:34

2009-05-08 10:41:37
2009-05-08 08:35:21

The 2009 eruption of Redoubt continues with declining geophysical indicators. Seismicity at the volcano has dropped over the past 36 hours, though it remains elevated. This change does not negate the possibility of an explosive eruption over the coming days.

There have been several reports of projectiles and plumes seen in the foothills at Redoubt. The FAA reports that there are military training operations going on in the area and they are using flares. This activity is not related to the eruption of Redoubt.

Vigorous steam and gas emissions are visible in web camera images this morning.

AVO is monitoring the situation closely and the observatory is staffed 24/7.

2009-05-08 03:28:20

The 2009 eruption of Redoubt continues with declining geophysical indicators. Seismicity at the volcano has dropped over the past 24 hours, though it remains elevated. This change does not reduce the possibility of an explosive eruption over the coming days.

There have been several reports of projectiles and plumes seen in the foothills at Redoubt. The FAA reports that there is military training operations going on in the area and they are using flares. This activity is not related to the eruption of Redoubt.

Vigorous steam and gas emissions are visible in web camera images.

AVO is monitoring the situation closely and the observatory is staffed 24/7.

2009-05-08 00:25:29

The 2009 eruption of Redoubt continues. Seismicity at the volcano has declined over the past 24 hours, but still remains elevated. This change does not reduce the possibility of an explosive eruption over the coming days.

There have been several reports of projectiles and plumes seen in the foothills at Redoubt. The FAA reports that there is military training operations going on in the area and they are using flares. This activity is not related to the eruption of Redoubt.

Vigorous steam and gas emissions are visible in web camera images.

AVO is monitoring the situation closely and the observatory is staffed 24/7.

2009-05-07 21:56:30

2009-05-07 20:19:58
2009-05-07 18:14:12
2009-05-07 14:48:19
2009-05-07 12:50:07

The 2009 eruption of Redoubt continues. Seismicity at the volcano has declined over the past 24 hours, but still remains elevated, Nearly continuous small earthquakes continued to recorded by stations near the summit. This decrease in the overall level of seismicity does not reduce the possibility of an explosive eruption over the coming days. Vigorous steam and gas emissions are visible in web camera images this morning. This plume may contain minor amounts of ash near the volcano, but no ash has been detected in satellite or radar data.

AVO is monitoring the situation closely and the observatory is staffed 24/7. AVO will provide frequent updates of the volcano's status and the earliest possible warning of significant explosive activity and other hazardous phenomena.

2009-05-07 12:14:21
2009-05-07 11:03:33
2009-05-07 09:57:09

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Redoubt Volcano Activity Notifications

2009-05-09 12:38:29 - Status Report

The 2009 eruption of Redoubt continues. Seismicity at the volcano has declined over the past 48 hours, but still remains elevated. Vigorous steam and gas emissions are visible in web camera images. This plume may contain minor amounts of ash near the volcano, but no ash has been detected in satellite or radar data.

AVO is monitoring the situation closely and the observatory is staffed 24/7. AVO will provide frequent updates of the volcano's status and the earliest possible warning of significant explosive activity and other hazardous phenomena.
Complete report text

2009-05-08 15:17:14 - Weekly Update

Growth of the lava dome continued this past week and is now roughly equivalent in size to the largest dome that was emplaced during the 1989-90 eruption. As the dome grows larger it is increasingly unstable with a growing likelihood of a complete or partial dome failure. Currently AVO considers renewed explosive activity and dome destruction as the most likely outcome of the current episode of dome growth. The return to explosive behavior may occur with little or no advanced warning and would produce a significant ash cloud and lahars and/or flooding in the Drift River valley. There is also a possibility that the current episode of dome growth will slowly diminish and no further explosive activity will occur. Based on our knowledge of past eruptions at Redoubt AVO considers this outcome to be less likely.

Seismicity has varied in its frequency, magnitude, and source characteristics over the past week, but remains consistent with continued dome growth. Numerous rock falls off the unstable north flank of the dome have been observed in seismic and web camera images this week, and have produced minor ash plumes that have reached heights of 12,000 ft above sea level (several thousand feet above the volcano). Vigorous venting of steam and other volcanic gases has been observed, and broad regions of sulfur dioxide gas have been detected by airborne gas measurement flights and in satellite images extending for hundreds of miles from the volcano. Thermal anomalies related to dome growth were observed in satellite data throughout the week.

AVO is monitoring the situation closely and the observatory is staffed 24/7. AVO will provide frequent updates of the volcano's status and the earliest possible warning of significant explosive activity and other hazardous phenomena.
Complete report text

2009-05-07 12:44:55 - Status Report

2009-05-06 14:12:37 - Daily Update

The 2009 eruption of Redoubt continues. Seismicity at the volcano has intensified in the last 24 hours, with nearly continuous small earthquakes now being recorded near the summit. Steam emissions have become increasingly vigorous over the last 24 hours. Satellite data from this morning show minor ash components in plume emissions. Rockfalls also continue to trigger ash emissions near the summit.

At approximately 22:00 AKDT on May 5 (0600 UTC May 6), there was a distinct increase in seismicity, with a near doubling in the intensity of volcanic tremor and a notable increase in the number of discrete events. At the same time, steam emissions greatly intensified and were briefly accompanied by vigorous ash emissions that did not exceed 12,000 feet above sea level.

AVO is monitoring the situation closely and the observatory is staffed 24/7. AVO will provide frequent updates of the volcano's status and the earliest possible warning of significant explosive activity and other hazardous phenomena.
Complete report text

2009-05-05 12:49:25 - Status Report

Current activity at Redoubt volcano suggests that a significant explosive event is likely, though not certain, in the coming days. The level of seismicity, rate of dome growth, and gas output indicate that an explosive event could occur at any time with little or no warning. Since about May 2, shallow earthquake activity beneath the actively growing lava dome has been slowly increasing. Recent observations indicate that small, ash-producing rockfalls from the dome's north side are becoming more frequent.

The seismic activity consists primarily of repetitive events occurring several times per minute as well as more continuous volcanic tremor. Similar seismicity was observed prior to several explosions earlier in the 2009 eruptive sequence and many of the explosive events during the 1989-90 eruption. The lava dome that has grown in the summit crater is now roughly equal in size to the largest dome that was emplaced during the 1989-90 eruption. As the dome grows larger it becomes increasingly unstable and is more and more likely to experience a complete or partial dome failure. A dome failure event could produce voluminous block and ash flows down Drift glacier and could generate significant amounts of meltwater.

Should a significant explosion, dome collapse, or both occur, the event will likely produce high altitude (>30,000 ft ASL) ash plumes, trace to minor ash fall in parts of south-central Alaska, lahars and flooding in the Drift River valley, and pyroclastic flows in the immediate vicinity of the volcano. The effects of the next explosive event or events could be similar to what has been observed so far during the 2009 eruption.

AVO is monitoring the situation closely and the observatory is staffed 24/7. AVO will provide frequent updates of the volcano's status and the earliest possible warning of significant explosive activity and other hazardous phenomena. The next AVO visit to the volcano is planned for May 7, weather permitting.
Complete report text

2009-05-05 06:59:43 - VAN/VONA

Current activity at Redoubt volcano suggests that a significant explosive event is likely, though not certain, in the coming days. This event could occur at any time with little or no warning. Since about May 2 shallow earthquake activity beneath the actively growing lava dome of Redoubt volcano has been slowly increasing. The growing lava dome is becoming increasingly unstable.

Should a significant explosion occur, the event will likely produce high altitude (>30,000 ft ASL) ash plumes, trace to minor ash fall in parts of south-central Alaska, lahars in the Drift River Valley, and pyroclastic flows in the immediate vicinity of the volcano.

AVO continues 24/7 operations and is monitoring the situation closely. AVO will provide frequent updates of the volcano's status and the earliest possible warning of significant explosive activity and other hazardous phenomena.
Complete report text

2009-05-04 13:09:31 - Status Report

The 2009 eruption of Redoubt volcano continues, with growth of a lava dome in the summit crater. Seismicity remains elevated and is characterized by frequent rockfall signals, numerous small earthquakes, and low levels of volcanic tremor. Clear web camera images show continuous steam emissions rising several thousand feet above the summit and currently moving towards the southeast. These steam emissions may contain minor amounts of ash, but they are too diffuse to be detected by radar. Satellite images show a persistent thermal anomaly consistent with an actively growing lava dome in the summit crater.

Additional explosive events producing ash clouds, ash fall, and mudflows are possible and can occur with little or no warning. AVO is maintaining 24/7 operations in order to quickly detect renewed significant explosive activity and other hazardous phenomena.
Complete report text

2009-05-03 11:13:08 - Status Report

The 2009 eruption of Redoubt volcano continues. Seismicity has increased markedly over the last 12 hours, including more frequent rockfall signals and small LPs. Clear webcam views have shown minor ash emissions during this period, with winds currently blowing to the south and west. Satellite views show a persistent thermal anomaly consistent with an actively growing lava dome in the summit crater.

Additional explosive events producing ash clouds, ash fall, and mudflows are possible and can occur with little or no warning. AVO is maintaining 24/7 operations in order to quickly detect renewed significant explosive activity and other hazardous phenomena.
Complete report text

More ...

2009-05-02 12:41:23 - Status Report

The 2009 eruption of Redoubt volcano continues. Seismic activity remains elevated and has changed little over the past 24 hours. Satellite views show a persistent thermal anomaly consistent with an actively growing lava dome in the summit crater. Occasional small rock avalanches from the lava dome are producing very minor ash emissions in the immediate vicinity of the volcano. Web camera views show a diffuse steam and gas plume rising to about the summit of the volcano and drifting southwest.

Additional explosive events producing ash clouds, ash fall, and mudflows are possible and can occur with little or no warning. AVO is maintaining 24/7 operations in order to quickly detect renewed significant explosive activity and other hazardous phenomena.
Complete report text

2009-05-02 09:48:22 - Information Statement

2009 Redoubt Eruption: Update and Prognosis, Saturday, May 2, 2009

Summary

The 2009 eruption of Redoubt Volcano continues. The last major explosion at Redoubt occurred at 05:55 AKDT April 4. Since then, a lava dome has been growing in the northern part of the summit crater. The shape of the dome when viewed from above is elliptical, with the long axis oriented approximately north-south. A tongue of lava that forms the northern tip of the dome has advanced about 550 yards (500 m) down the Drift Glacier Gorge. The volume of the dome as of early May is approximately 25 - 30 million cubic meters. Renewed explosive activity remains a possibility, and could occur with little or no warning. Such activity would likely result in ash plumes exceeding 30,000 feet (9000 m) above sea level, lahars down the Drift River Valley, and trace to minor ash fall on communities near Redoubt.

Observations

Since the Information Statement of April 11, 2009, AVO field workers have collected new data of several different types, including geologic observations, geodetic measurements, thermal imagery, radar profiles, and satellite views. AVO continues to log seismic data, conduct periodic gas measurements, and make air quality and particulate content measurements. AVO also analyzes all data collected at Redoubt for the purposes of both basic research into volcanic processes and improvements in our forecasting and warning capability.

Observations of the lava dome suggest that it is similar in size and character to the dome that grew between about January 10 and February 15, 1990. Hot blocks shed from the northern edge of the lava dome have accumulated in the Drift Glacier Gorge. This process of rock falls has occasionally generated very minor, localized ash and steam plumes, often visible in the webcam and responsible for occasional dustings of ash on surrounding terrain. A secondary steam-and-ash plume originating about 4000 feet (1220 m) above sea level on the ridge to the west of the Drift Glacier was intermittently visible on AVO's web cameras from about April 5 through April 10. Field observations revealed that this short-lived feature resulted from hot pyroclastic debris, deposited during the April 4 explosion, sifting down into glacial crevasses where it caused minor steam and ash explosions. Observations in the Drift River Valley indicate that the lahar of April 4 was large enough to extend across the entire valley, toppling trees and leaving high-water marks more than 30 feet (10 m) above the active channel.

On April 16, AVO recovered data collected by Global Positioning System (GPS) receivers that had been placed around Redoubt in late February. Retrospective analysis shows that in late March 2009, coincident with the onset of explosive eruption, these GPS instruments recorded a distinct "deflationary" signal. This deflation likely results from the draining of a magma chamber in the mid- to upper-crust. The draining -- or emptying -- of the magma chamber occurs as lava and ash are erupted from the volcano. More than 1 inch (2 cm) of ground movement, directed down and toward the center of the volcano, have been recorded since late March at a station on the east flank of Redoubt. The rate of deformation appears to have slowed starting in early April. In the coming days, AVO will recover additional data from these instruments, which will span the interval from April 16 onward.

Also, on April 16, AVO conducted Forward Looking Infrared (FLIR) measurements of Redoubt's lava dome. The maximum observed temperature was about 420°C (790°F) on the dome's north face. This reading is not a direct measurement of actual lava temperature as it emerges from the vent, which is known to be considerably higher (~850 - 950 °C), but rather a temperature measurement of the cooling crust of new rock that surrounds the extruding magma. Along with providing spot temperature readings, FLIR data also allows AVO to estimate the dimensions of the growing lava dome by clearly delineating the very hot, new rock from the cool background. These measurements, combined with data from RADARSAT2, result in estimated dome dimensions on April 16 of about 1650 ft (500 m) by 2300 ft (700 m) and 500 ft (150 m) thick. Note that recently collected satellite data as well as web cam views show that the dome has grown substantially in the two weeks since these FLIR data were acquired. The volume of the dome and northward flowing lava tongue are now about 25 to 30 million cubic meters.

Seismic activity since April 4 has consisted of numerous shallow events of a distinctly volcanic character, along with some deeper "rock-breaking" earthquakes. The shallow activity likely occurs within 0.5 to 1.5 miles (1 to 2 km) of the summit crater floor and is thought to arise from the ongoing flow of magma into the growing lava dome. The magnitudes of the shallow events range from 0.1 to 1.0, with most being too small to locate. The deeper earthquakes generally range in depth from 3 to 6 miles (5 to 10 km) below sea level, with magnitudes between from 0.2 to 1.8. These deeper earthquakes are indicative of brittle rock fracture, and are thought to represent a stress adjustment to removal of magma from these depths that is feeding the ongoing eruption. AVO has also detected several deeper events at about 19 miles (31 km) beneath Redoubt. These events suggests that magmatic processes are still active at the base of the Earth's crust -- the uppermost layer of the Earth that extends to about 26 miles (40 km) depth in this part of the world -- and that all portions of the Redoubt magmatic system continue to respond to the current eruptive sequence.

AVO has made three fixed-wing gas observation flights on April 16, April 20, and April 28. Measurements from all flights continue to show elevated levels of volcanic gas emission, though the rate of SO2 emission declined from greater than 10,000 tonnes/day to about 2,500 tonnes/day on April 16. On subsequent flights, however, the SO2 emission rate climbed back to approximately 10,000 tonnes/day. CO2 emissions remained fairly consistent over the interval, with the rate ranging between 10,000 to 15,000 tonnes/day.

During clear to partly cloudy weather, satellite observations from NOAA's AVHRR and GOES satellites have shown persistent areas of elevated surface temperature (thermal anomalies) in the dome area at Redoubt. Also during good weather, AVO's web camera located on the observation hut at 5000 feet (1500 m) above sea level and 7 miles north (11.5 km) of Redoubt's summit shows nighttime incandescence radiating from the dome.

Prognosis and Ongoing Hazards

The longest hiatus between explosions during the 1989-1990 eruption was 36 days. In comparison, as of this writing, 28 days have elapsed since the April 4 explosion. Then, as now, dome growth continued through the hiatus, and while dome growth is ongoing, a dome collapse or failure is very likely. If this occurs, an explosive and/or ash-producing event will soon follow, originating from either the vent region at the summit, the disintegrating dome remnants as they tumble down the Drift Glacier Gorge, or from a combination of both. Therefore, AVO considers additional explosive events likely. These events will, as before, produce ash columns tens of thousands of feet tall, with the potential for ash fall on nearby Alaska communities and the possible disruption of air traffic. The lahar danger still exists, particularly immediately following dome failures, but also to a lesser extent during times of quiescence. Between ash-producing events, residents and pilots may also notice an occasional sulfur smell and hazy conditions due to low-level ash and volcanic gas emissions. There is also a possibility that the current episode of dome growth will slowly diminish and no further explosive activity will occur. Based on our knowledge of past eruptions at Redoubt, AVO considers this outcome to be less likely.

Status of Instrumentation

Monitoring capabilities at Redoubt remain strong. Two seismometers and a continuous Global Positioning System (GPS) receiver that were damaged by lightning discharge during the March 23 explosion were repaired on April 16. The real-time network consists of 9 seismometers, a pressure sensor, and 2 web cameras. The Hut camera has a remotely controllable zoom lens that allows close-up imaging of the lava dome. There are 4 additional seismometers, 3 additional GPS receivers, and 1 time-lapse camera that record and store data on site. One of these GPS sites will be upgraded to a continuous telemetered site in the next few weeks. Work at this site and collection of data from instruments with on-site recording will occur as weather and safety conditions permit.
Complete report text

2009-05-01 14:50:15 - Weekly Update

The 2009 eruption of Redoubt Volcano continues. During the past week, growth of the lava dome within the summit crater was confirmed by changes in the shape and size of the dome. Seismic activity remains elevated above background levels reflecting the ongoing process of dome growth and occasional rock falls and avalanches of hot blocks. Satellite images show persistent thermal anomalies, consistent with an actively growing lava dome in the summit crater. Occasional small rock avalanches from the lava dome have produced minor ash emissions in the immediate vicinity of the volcano. Such rock fall events have been observed in the Hut web camera and one was observed directly yesterday, by an AVO field crew, while at the camera station.

Clear web camera views this week have also shown a consistent gas and steam plume rising to about the summit of the volcano. Airborne gas measurements on April 28 indicate that emission of sulfur dioxide and carbon dioxide remain elevated and similar to previous measurements.

On Thursday April 30, AVO geologists sampled ash-fall deposits and worked on lahar deposits in the mid and lower Drift River Valley. Dome temperature measurements were made using a forward looking infrared (FLIR) camera and those data are being processed. In addition, the field crew retrieved and replaced data cards from three GPS stations.

The current Redoubt eruption is expected to continue for weeks to months. During this time, a cycle of relatively quiet periods of lava dome growth followed by explosive episodes of dome destruction will likely take place. Future explosions pose an ongoing threat of lahars in the Drift River Valley, trace to minor ash fall throughout south-central Alaska, and ash-related impacts to aviation. AVO is maintaining 24/7 operations in order to quickly detect renewed significant explosive activity and other hazardous phenomena.
Complete report text

2009-04-30 13:19:03 - Status Report

The eruption of Redoubt volcano continues. Seismic activity remains elevated and has changed little over the past 24 hours. Satellite views show a persistent thermal anomaly consistent with an actively growing lava dome. Occasional small rock avalanches from the lava dome are producing very minor ash emissions in the immediate vicinity of the volcano. Web camera views show a diffuse steam and gas plume rising to about the summit of the volcano and drifting northwest. AVO has two field crews working at the volcano today.

Additional explosive events producing ash clouds, ash fall, and mudflows are possible and can occur with little or no warning. AVO is maintaining 24/7 operations in order to quickly detect renewed significant explosive activity and other hazardous phenomena.
Complete report text

2009-04-29 12:06:40 - Status Report

The eruption of Redoubt volcano continues. Seismic activity remains elevated and has changed little over the past 24 hours. Satellite views show a thermal anomaly consistent with the presence of an actively growing lava dome. Occasional small rock avalanches are occurring off the north side of the lava dome and these are producing some seismicity and minor low level ash emissions but only in the immediate vicinity of the volcano. Web camera views show a diffuse steam plume rising to about the summit of the volcano.

Additional explosive events producing ash clouds, ash fall, and mudflows are possible and can occur with little or no warning. AVO is maintaining 24/7 operations in order to quickly detect renewed significant explosive activity and other hazardous phenomena.
Complete report text

Color Code and Alert Level Definitions

Webcams

Redoubt - Hut

Redoubt - CI

Redoubt - DFR

Click to view larger images.

Webicorders

Stations available:
RSO_EHZ_AV
RDN_EHZ_AV
REF_EHZ_AV
NCT_EHZ_AV

RSAM

REF_EHZ_AV - Seismic station REF, beginning Jan. 24, 6 hour average.

REF_EHZ_AV - Seismic station REF, last 7 days, 10 minute average.

NOAA ARL Ash Trajectory Forecasts

+12

+18

+24

These graphics depict a simulation of the direction and speed of potential ash cloud motion from Redoubt. IF a significant ash cloud were generated by the current eruption. It does not mean that such an ash cloud has been produced. These models are run every 6 hours independent of the current eruptive state of the volcano. Each colored line indicates the direction a cloud would travel at different altitudes (see key below map plot).

Here is how to convert from UTC to AKDT (Alaska Daylight Time):

0000 UTC= 4:00 PM AKDT on the previous day as UTC
0600 UTC= 10:00 PM AKDT on the previous day as UTC
1200 UTC= 4:00 AM AKDT on the same day as UTC
1800 UTC= 10:00 AM AKDT on the same day as UTC

Model output by NOAA ARL, please see http://www.arl.noaa.gov/ready/traj_alaska.html for more information.

Redoubt portion of weekly Updates and periodic Information Releases.

April 2009 Updates

Friday, April 24, 2009 4:02 04:02:23 PM AKDT

The 2009 eruption of Redoubt Volcano continues. During the past week, growth of the lava dome within the summit crater has slowed based on observations of little change in dome shape. Using a Radarsat2 image from April 20 and thermal images obtained on April 16, the current dome is estimated to be about 500 m (1640 ft) by 700 m (2297 ft) and 150 m (500 ft) thick. Emissions of volcanic gases and minor amounts of ash continues. A probable rockfall from the lava dome generated a very localized dusting of ash early today. The aviation color code remains ORANGE and the alert level WATCH. AVO continues to monitor the situation closely and the observatory is staffed 24/7. The last explosive event during the current eruption occurred on the morning of April 4 (05:55 AKDT). Since then, seismicity has remained elevated above background reflecting the ongoing process of dome growth and occasional rock falls. The nearly constant vapor and gas cloud rising above the volcano has remained mostly below 15,000 feet above sea level. Satellite images show thermal anomalies at the summit as well as the low -level plumes and sulfur dioxide clouds drifting away from the volcano. Airborne gas measurements on April 20 indicate that emission of sulfur dioxide and carbon dioxide has increased since the previous measurement on April 16. On Tuesday, April 21, an AVO field crew repaired a GPS station at the research hut (webcam location) that had been damaged in the March 23 explosion. In addition, they retrieved data cards from other GPS stations and the Dumbbell Hills time lapse camera. AVO geologists sampled material from the last explosive event and lahar deposits in the Drift River Valley. Additionally, high-water marks were measured from the flow down Drift River on April 4. The flow averaged about 10 m (33 ft) in depth at mid-valley. The current Redoubt eruption is expected to continue for weeks to months. During this time, a cycle of relatively quiet periods of lava dome growth followed by explosive episodes of dome destruction will likely take place. Future explosions pose an ongoing threat of lahars in the Drift River Valley, trace to minor ash fall throughout south-central Alaska, and ash-related impacts to aviation. Heavily ice-mantled Redoubt volcano is located on the western side of Cook Inlet, 170 km (106 mi) southwest of Anchorage and 82 km (51 mi) west of Kenai, within Lake Clark National Park. Redoubt is a stratovolcano which rises to 10,197 feet above sea level. Recent eruptions occurred in 1902, 1966-68, and 1989-90. The 1989-90 eruption produced mudflows, or lahars, that traveled down the Drift River and partially flooded the Drift River Oil Terminal facility. The ash plumes produced by the 1989-90 eruption affected aviation and resulted in minor or trace amounts of ash in the city of Anchorage and other nearby communities.

Friday, April 17, 2009 1:45 01:45:01 PM AKDT

The 2009 eruption of Redoubt Volcano continues. Over the past week, a lava dome has continued to grow in size within the summit crater. Based on photography and thermal images obtained yesterday, the current dome is estimated to be about 500 m (1640 ft) by 700 m (2297 ft) and at least 50 m (160 ft) thick. Dome growth during the past week has been accompanied by intermittent emissions of volcanic gases and minor amounts of ash. The aviation color code remains ORANGE and the alert level WATCH. AVO continues to monitor the situation closely and the observatory is staffed 24/7. The last explosive event during the current eruption occurred on the morning of April 4 (05:55 AKDT). Since then, seismicity has remained elevated above background reflecting the ongoing process of dome growth and occasional rock falls. The nearly constant vapor and gas cloud rising above the volcano has remained mostly below 15,000 feet above sea level. Satellite images show thermal anomalies at the summit as well as the low -level plumes and sulfur dioxide clouds drifting away from the volcano. Over the week, pilots have noted occasional sulfur smell down wind. On Thursday, April 16, AVO field crews repaired a summit seismic station (RSO) that had been destroyed in the March 23 explosion. In addition, they installed a new camera at the AVO hut that has remote zooming capabilities. AVO geologists sampled material from the last explosive event and investigated the site of a smaller ash and water vapor plume seen intermittently down slope from the summit earlier over the past two weeks. Based on their observations, it appears that this secondary plume was the result of hot pyroclastic debris falling into a crevasse in glacial ice. Also on Thursday, April 16, AVO completed a gas measurement flight. The current Redoubt eruption is expected to continue for weeks to months. During this time, a cycle of relatively quiet periods of lava dome growth followed by explosive episodes of dome destruction will likely take place. Future explosions pose an ongoing threat of lahars in the Drift River Valley, trace to minor ash fall throughout south-central Alaska, and ash-related impacts to aviation.

Friday, April 10, 2009 11:59 11:59:49 AM AKDT

The 2009 eruption of Redoubt Volcano continues. Satellite and other evidence indicate a lava dome is growing in the summit crater. Additional explosive activity is possible with little warning. The aviation color code remains ORANGE and the alert level WATCH. AVO continues to monitor the situation closely and the observatory is staffed 24/7. Seismicity at the volcano has remained relatively steady following the last explosion on the morning of April 4 with small repetitive volcanic earthquakes dominating the signal. A continuous plume of volcanic gas, water vapor, and variable but small amounts of ash is being emitted from the vent. The resulting cloud is rising to variable altitudes over the volcano, but mostly less than 15,000 feet above sea level. Pilots have reported occasional sulfur smells downwind of the volcano. Weather has prevented additional AVO overflights most of the week. Based on its past activity, the current Redoubt eruption is expected to continue for weeks to months. During this time, a cycle of relatively quiet periods of lava dome growth followed by explosive episodes of dome destruction will likely take place. Future explosions pose an ongoing threat of lahars in the Drift River Valley, trace to minor ash fall throughout south-central Alaska, and ash-related impacts to aviation.

Monday, April 6, 2009 2:55 02:55:36 PM AKDT

The eruption of Redoubt continues with varying intensity of ash and lava production from the summit crater. Additional significant explosive events with accompanying ash clouds, ash fall, and mudflows are possible and can occur with little or no warning. Visual, satellite, and seismic observations indicate that a lava dome is again forming in the summit crater. The character of current seismicity suggests that a sudden explosive eruption is not imminent. Present levels of activity are emitting only a very minor amount of ash that poses a hazard of limited aerial extent. Consequently, AVO is lowering the Aviation Color Code to ORANGE and the Alert Level to WATCH. AVO will maintain 24/7 operations in order to quickly detect renewed significant explosive activity and other hazardous phenomena. Intermittent views by the AVO web camera earlier today show a continuous plume composed primarily of water vapor and gas rising above the summit to less than 15,000 feet and drifting northeast. Please see the National Weather Service Redoubt coordination page http://pafc.arh.noaa.gov/volcano.php for the latest ash fall information.

Saturday, April 4, 2009 6:51 06:51:43 AM AKDT
Saturday, April 4, 2009 6:35 06:35:41 AM AKDT
Friday, April 3, 2009 3:04 03:04:54 PM AKDT

The 2009 eruption of Redoubt Volcano continues. Over the past several days, the intensity of ash-production has decreased while a lava dome is growing in the summit crater. Therefore, Alaska Volcano Observatory (AVO)lowered the alert level to WATCH and aviation color code to ORANGE this morning. AVO continues to monitor the situation closely and the observatory is staffed 24/7. Following last Friday's update, Redoubt had seven more powerful ash explosions through Saturday evening, with the resulting plumes reaching between 25,000 to 50,000 feet above sea level. In total, AVO has observed 18 major explosive events since the start of the eruption. The last major explosive event occurred at 19:23 AKDT on March 28 (03:23 UTC, March 29). Over the last few days, a diffuse cloud of volcanic gas, ash, and steam is rising to variable altitudes over the volcano, but mostly less than 15,000 feet above sea level. At times of more vigorous ash production, the cloud has risen as high as 25,000 feet. Lightning has been detected several times in conjunction with ash emission this week. Trace amounts of ash fall (less than 0.8 mm or less than 1/32 inch) have been reported at Kenai and at Valdez. The area in the immediate vicinity of the volcano is blanketed by a thin layer of ash visible in the AVO web cameras. The larger explosions produced lahars in the Drift River Valley and minor ash fall in areas across south-central Alaska including Anchorage. A broad layer of volcanic haze extended east of the volcano over the Kenai Peninsula, the Anchorage Bowl, and the Matanuska-Susitna Valley on March 31. AVO overflights and photography have confirmed that a lava dome is actively growing in the summit crater. Occasional avalanches of hot blocks tumbling from the dome are traveling a short distance down the north flank of the volcano. Seismicity at the volcano had been declining over the course of the week until around 8:00 AM AKDT Thursday morning. Since then small repetitive volcanic earthquakes have been visible on stations closest to the summit crater. These earthquakes have continued up to the time of this report. Based on its past activity, the current Redoubt eruption is expected to continue for weeks to months. During this time, a cycle of relatively quiet periods of lava dome growth followed by explosive episodes of dome destruction will likely take place. Future explosions pose an ongoing threat of lahars in the Drift River Valley, trace to minor ash fall throughout south-central Alaska, and ash-related impacts to aviation.

Friday, April 3, 2009 11:44 11:44:52 AM AKDT

The eruption of Redoubt Volcano continues. Over the past several days, the intensity of ash-production has decreased. Current observations indicate a lava dome is growing in the summit crater. Therefore, we are lowering the alert level and aviation color code. The 2009 eruption is now characterized by continuous emission of steam, volcanic gas, and variable amounts of ash. These processes are occurring as effusion of lava in the summit crater produces a lava dome. While at this level of activity, trace amounts of ash and a perceptible volcanic haze layer may be intermittently present throughout south-central Alaska. A growing lava dome is inherently unstable; a sudden dome collapse or explosion can occur with no warning and produce a more voluminous ash cloud that rises to elevations above 25,000 feet. If such an event is detected, AVO would issue appropriate warnings.

March 2009 Updates

Monday, March 30, 2009 10:12 10:12:07 AM AKDT
Monday, March 30, 2009 5:14 05:14:47 AM AKDT
Sunday, March 29, 2009 11:35 11:35:01 PM AKDT
Saturday, March 28, 2009 7:36 07:36:47 PM AKDT
Saturday, March 28, 2009 3:43 03:43:32 PM AKDT
Saturday, March 28, 2009 1:58 01:58:10 PM AKDT
Saturday, March 28, 2009 1:29 01:29:44 AM AKDT
Friday, March 27, 2009 11:54 11:54:02 PM AKDT
Friday, March 27, 2009 11:29 11:29:45 PM AKDT
Friday, March 27, 2009 7:34 07:34:04 PM AKDT
Friday, March 27, 2009 5:49 05:49:31 PM AKDT
Friday, March 27, 2009 3:43 03:43:42 PM AKDT

The 2009 eruption of Redoubt Volcano, which began on March 22 at 22:38 AKDT (6:38 UTC March 23), continues. The eruption has been characterized by powerful ash explosions, with the resulting plumes reaching between 30,000 to 60,000 feet above sea level. In all, the Alaska Volcano Observatory (AVO) has observed 11 major explosive events over the last week. The larger explosions have been associated with lahars in the Drift River Valley and trace to minor ash fall in and around the volcano and in areas across south-central Alaska. There have been no explosions of Redoubt Volcano since this morning March 27 at approximately 08:40 AKDT (16:40 UTC) and seismicity has declined at the volcano. The National Weather Service continues to track the ash cloud from the latest explosion, which is tracking toward the north-northwest. For ash fall advisories, refer to the National Weather Service Redoubt Coordination web page http://pafc.arh.noaa.gov/volcano.php AVO is monitoring the situation closely and the observatory is staffed 24/7. Based on its past activity, the current Redoubt eruption is expected to continue for weeks to months. During this time, a cycle of relatively quiet periods of lava dome growth followed by explosive episodes of dome destruction could take place. Future explosions pose an ongoing threat of lahars in the Drift River Valley, trace to minor ash fall throughout south-central Alaska, and ash-related impacts to aviation.

Friday, March 27, 2009 8:51 08:51:49 AM AKDT
Friday, March 27, 2009 12:00 12:00:37 AM AKDT
Thursday, March 26, 2009 9:42 09:42:14 AM AKDT
Thursday, March 26, 2009 8:56 08:56:56 AM AKDT
Wednesday, March 25, 2009 1:35 01:35:06 PM AKDT

Seismic activity at Redoubt Volcano has declined over the last 36 hours, although there have been several brief increases in seismicity associated with minor low-level ash emissions. The last known ash emission was at 5:12 AKDT this morning. The plume from this event did not extend above about 15,000 feet. Based on the level of seismic activity, AVO is lowering the aviation color code to ORANGE and the volcanic alert level to WATCH. Current seismicity at Redoubt is at times suggestive of intermittent lava extrusion at the volcano's summit. However, the existence of a new lava dome has not been confirmed because of poor weather. Growth of lava domes is common at volcanoes like Redoubt and was observed several times throughout the last eruption of 1989-1990. As dome size increases, so does the possibility of dome collapse along with a return to a more explosive eruptive style. Though a distinct rise in seismicity often precedes dome failure, domes can fail with little or no warning and may result in a sudden explosion and ash emission. Based on observations from the Redoubt eruption of 1989-1990, episodes of dome growth followed by explosive dome destruction is a likely but by no means certain, near-term scenario. Cycles of dome growth and failure could occur for several months. In the event of an escalation in seismic activity or confirmation of a significant ash producing eruption, AVO would accordingly raise the color code and alert level to Red/Warning. It is possible that dome collapse events will initiate pyroclastic flows over Drift glacier that will result in meltwater generation and downstream mudflows and floods. Some of these floods could reach Cook Inlet within hours.

Wednesday, March 25, 2009 5:53 05:53:13 AM AKDT
Monday, March 23, 2009 8:14 08:14:56 PM AKDT

Another phase of vigorous ash eruption at Redoubt Volcano began at 7:41 pm (AKDT). AVO remains at Aviation Color Code RED and Alert Level WARNING. The top of the ash cloud is estimated to be at least 50,000 ft above sea level based on NWS radar. Winds in the vicinity of the volcano vary with altitude and are expected to carry the ash cloud primarily to the west and north. Seismicity has declined somewhat since the start of the event but remains elevated. AVO remains staffed 24 hours per day will issue further information as it becomes available. For up-to-date Ashfall Advisories and wind trajectories, please refer to the National Weather Service website: http://pafc.arh.noaa.gov/volcano.php

Sunday, March 22, 2009 11:26 11:26:32 PM AKDT
Sunday, March 22, 2009 10:56 10:56:25 PM AKDT
Saturday, March 21, 2009 10:09 10:09:44 PM AKDT
Friday, March 20, 2009 12:02 12:02:14 PM AKDT

On Sunday, March 15, 2009, AVO raised the color code and alert level to ORANGE/Warning during an abrupt increase in seismicity and following a burst of steam and ash that was observed by airborne AVO staff. High volcanic gas emissions were measured during the event. After several hours, seismicity and steam emissions declined, and remained low for the next several days. The color code and alert level was subsequently reduced to YELLOW/Advisory on March 18, 2009. Seismic activity at Redoubt has been low over the remainder of the week but remains above background levels. The seismicity consists of occasional short periods of low amplitude volcanic tremor and small discrete earthquakes. A burst of several dozen larger events occurred Friday morning. Mostly clear weather at the volcano this week has provided good satellite and web camera images, and these showed nothing unusual. A steam plume rising just above the summit of the volcano has been visible most of the week. It is still possible for unrest at the volcano to change rapidly, and seismic activity or other signs of unrest could escalate over time periods as short as 24 hours or less. AVO continues to monitor Redoubt closely, but the AVO operations center in Anchorage is no longer formally staffed 24 hours per day, although someone is on duty 24 hours per day and can be contacted by calling 907-786-7497. Heavily ice-mantled Redoubt volcano is located on the western side of Cook Inlet, 170 km (106 mi) southwest of Anchorage and 82 km (51 mi) west of Kenai, within Lake Clark National Park. Redoubt is a stratovolcano which rises to 10,197 feet above sea level. Recent eruptions occurred in 1902, 1966-68, and 1989-90. The 1989-90 eruption produced mudflows, or lahars, that traveled down the Drift River and partially flooded the Drift River Oil Terminal facility. The ash plumes produced by the 1989-90 eruption affected international air traffic and resulted in minor or trace amounts of ash in the city of Anchorage and other nearby communities.

Wednesday, March 18, 2009 9:41 09:41:36 AM AKDT

The Alaska Volcano Observatory is lowering the Aviation Color Code to YELLOW and the Alert Level to Advisory for Mount Redoubt. Following the steam and ash emission on Sunday, March 15, seismicity has declined to levels prior to that event, and no additional emissions have been observed in web camera or satellite images. The new magma beneath the volcano does not show signs of upward movement at this time. The volcano remains restless with abnormally high rates of gas emission and continued melting of the summit glacier. It is still possible for the current period of unrest to result in an eruption. However, the type of unrest we have observed so far could persist for many months to a year or more and not lead to an eruption. It is possible for conditions at the volcano to change rapidly, advancing from relatively low levels of activity to eruption in time periods as short as 24 hours or less. AVO will continue to monitor Redoubt closely, but will no longer be formally staffed 24 hours per day.

Sunday, March 15, 2009 2:50 02:50:14 PM AKDT

Seismic activity at Redoubt has increased since about 13:00 AKDT and is continuing. An AVO observation flight reported that a steam and ash plume rose as high as 15,000 ft above sea level and produced minor ash fall on the upper south flank of Redoubt. Last reports are that the plume is now mainly steam. Based on this change in activity AVO is increasing the level of concern and alert level to ORANGE/WATCH. It does not appear at this time that a significant eruption is likely in the short term, but conditions may evolve rapidly. AVO is monitoring the situation closely and the AVO operations center in Anchorage is now resuming 24 hour per day staffing.

Friday, March 13, 2009 2:09 02:09:51 PM AKDT

On Tuesday, March 10, 2009, AVO lowered the color code and alert level to yellow/advisory on the basis of declining seismcity, heat output, and no significant change in gas emission. An information statement describing the current status of the volcano and potential for future activity was released yesterday. Seismic activity at Redoubt has been low over the past week but remains above background levels. The seismicity consists of occasional short periods of low amplitude volcanic tremor and small discrete earthquakes interspersed between periods of no seismic activity. It has been cloudy over the volcano most of the week and only a few clear views were possible by satellite and web camera, and these showed nothing unusual. Yesterday afternoon, a steam plume rising just above the summit of the volcano was visible by web camera. It is still possible for unrest at the volcano to change rapidly, and seismic activity or other signs of unrest could escalate over time periods as short as 24 hours or less. AVO continues to monitor Redoubt closely, but the AVO operations center in Anchorage is no longer formally staffed 24 hours per day, although someone is on duty 24 hours per day and can be contacted by calling 907-786-7497.

Tuesday, March 10, 2009 9:56 09:56:59 AM AKDT

The Alaska Volcano Observatory is lowering the Aviation Color Code to YELLOW and the Alert Level to Advisory for Mount Redoubt. The new magma beneath the volcano does not show any signs of upward movement at this time. The volcano remains restless with abnormally high gas emission rates and melting of the summit glacier still evident. It is still quite possible, though far from certain, that the current volcanic unrest at Mount Redoubt could result in an eruption. Also, this unrest could persist for many months to a year or more and not lead to an eruption. During this unrest, it is possible for unrest at the volcano to change rapidly, advancing from relatively low levels to eruption in time periods as short as 24 hours or less. AVO will continue to monitor Redoubt closely, but will no longer be formally staffed 24 hours per day.

Friday, March 6, 2009 1:40 01:40:46 PM AKDT

Redoubt Volcano remains in a restless state. The level of seismic activity has declined somewhat this week but is still above background levels. Seismic activity consists of small discrete earthquakes, and little to no volcanic tremor. There have been no significant earthquake swarms over the past week, and no new hydrologic or glaciologic events related to ice melt have occurred. Clouds have obscured views of the volcano by web camera and satellite most of the week. AVO continues to monitor Redoubt closely and the observatory will be staffed 24 hours per day while the volcano is at an elevated level of unrest.

February 2009 Updates

Friday, February 27, 2009 1:31 01:31:27 PM AKDT

Unrest at Redoubt Volcano continues. No eruption has occurred. Relatively low-amplitude volcanic tremor and intermittent discrete earthquakes characterized seismic activity at Redoubt from February 21-24. During this time, clear weather allowed many web camera and satellite views that showed nothing out of the ordinary. On Wednesday, February 25, a broad-spectrum seismic signal at 9:29 AM AKST was likely associated with a small mud flow originating from a melt hole in the Drift glacier at about 5600 feet above sea level. This dark deposit was seen in a web camera image from 10:03 AM AKST that morning, and observers on an overflight the next day reported that the deposit was several hundred meters in length. Later the same day, at 3:37 PM AKST, tremor amplitude increased sharply and remained elevated for approximately one hour. This tremor was strong enough to be recorded on all seismic stations on Redoubt Volcano as well as many stations surrounding Cook Inlet. At 10:40 PM AKST the same night, the number of discrete earthquakes increased and remained elevated for about four hours. On Thursday, February 26, a flurry of earthquakes began at 5:30 PM AKST and lasted for roughly one hour. These events were accompanied by the emplacement of a mudflow that covered a large portion of the upper Drift glacier, as viewed in web camera images beginning at 6:04 PM AKST. An ASTER thermal infrared satellite image from last night shows this deposit stretching several kilometers down the Drift glacier. The recent variations in seismic activity coupled with increased melt water discharge on the upper Drift glacier indicate that conditions have changed at shallow depths beneath the volcano. It is possible that magma has moved to shallower levels in the volcanic edifice, but recent changes may be due instead to changes in degassing pathways from a deeper magma body. AVO is currently analyzing this seismic activity and will issue further information as it becomes available. A gas-measurement flight is currently underway. Because of the clear weather this past week, AVO was able to undertake several flights to Redoubt to measure gas (February 21, and today) and perform upgrades to the monitoring network (February 21, 22, and today). Results from the February 21 gas flight reveal that the emission rates of CO2 and SO2 have not changed since February 7 and both remain high. Upgrades to the network include addition of a broadband seismometer on the volcano's west flank, installation of a pressure sensor (to detect airwaves) north of the volcano, and improvements to the power supply at the AVO hut. AVO continues to monitor Redoubt Volcano closely, and the observatory is staffed 24 hours a day.

Friday, February 20, 2009 1:21 01:21:00 PM AKDT

Unrest at Redoubt Volcano continues. No eruption has occurred. Volcanic tremor with variable amplitudes and intermittent discrete earthquakes occurred continuously throughout the week. The strongest tremor occurred February 16-18. Satellite views of Redoubt were largely obscured by clouds throughout the week. A few clear images showed nothing unusual. Webcam views have been obscured by snow and ice. This level of activity is similar to what we have observed over much of the current period of unrest. No field work was done at Redoubt this week. A gas-measurement flight is now scheduled for tomorrow, Saturday February 20, if weather permits. AVO continues to monitor Redoubt Volcano closely, and the observatory is staffed 24 hours a day.

Friday, February 13, 2009 2:24 02:24:07 PM AKDT

Unrest at Redoubt Volcano continues, though no eruption has yet occurred. Seismic activity at the volcano remains above background levels. This week, seismicity has been dominated by periods of tremor with variable amplitudes and small discrete earthquakes. These data are likely indicative of movement of shallow fluids (including heated ground water) and gases within the volcano. Web camera views have been obscured by clouds and snow since Tuesday. Clear web camera views and reports from staff observers in the field during the past week reported intermittent steam plumes from the area of the 1989-90 lava dome and from a new melt hole, continued melting of the upper Drift glacier, and continued water discharge along the lower Drift glacier and into the Drift River. Airborne gas measurements on February 7 recorded levels of the magmatic gas CO2 about two times greater than the values recorded on January 31 and February 2, 2009. Sulfur dioxide (SO2) levels remained low indicating that the gas is being absorbed by shallow groundwater near the volcano's summit. AVO personnel installed a GPS instrument near Redoubt and collected water samples and temperature data with an infrared camera. Sulfur odor was detected during sampling, which is consistent with the water carrying dissolved sulfur gas emitted in the active fumarolic zone. Exposed rock in the active fumaroles is warm (about 80 F)and the outflow stream on the west side of the Drift Glacier was frozen. Gas and heat flux, combined with ongoing seismic activity, suggest that new magma has been emplaced within the crust below Redoubt and that it is actively degassing. We estimate that the magma is still relatively deep (greater than 5 km or ~3 miles) although a small amount of the magma may have risen to shallower depths (within 2 km, or about a mile, of the surface) in late January when seismicity, degassing, and melting intensified. At present, the current period of elevated unrest could persist for some time, possibly many months. However, as long as substantial volcanic-gas emission, prolonged periods of tremor, and intermittent discrete, shallow earthquakes occur, notable escalation of activity immediately prior to an eruption might only be on the order of hours or less. On the basis of current activity, we consider the most likely scenario is an eruption similar to or smaller than the 1989-90 eruption. Staff continue to monitor the volcano 24 hours a day. We will issue further information as it becomes available. An Information Statement summarizing AVO's current analysis of unrest at Redoubt Volcano was released 13 February at 10:12AM AKST (today) and can be found on our web site: http://www.avo.alaska.edu/

Friday, February 6, 2009 1:05 01:05:32 PM AKDT

Unrest at Redoubt Volcano continues, though no eruption has yet occurred. Seismic activity at the volcano remains above background levels and has waxed and waned over the last week. Yesterday from 11:18 to about 16:00 AKST, there were several periods of more intense seismic tremor. Since then, nearly continuous low-level seismic tremor has been recorded. Clear web camera images currently show no activity at the volcano. Observers on overflights during the past week reported intermittent steam plumes from the area of the 1989-90 lava dome, continued melting of the upper Drift glacier, and increased water discharge along the lower Drift glacier and into the Drift River. Airborne gas measurements on January 31 and February 2 recorded levels of the magmatic gas CO2 several times greater than the value recorded on November 2, 2008. Gas and heat flux, combined with ongoing seismic activity, suggest that new magma has been emplaced within the crust below Redoubt and that it is actively degassing. We do not know the exact depths or volume of the magma; nor is it certain that the magma will continue to rise to the surface. On the basis of current activity, however, the most likely scenario is an eruption similar to or smaller than the 1989-90 eruption. It is somewhat less likely that no eruption will occur or that the volcano has an eruption larger than that of 1989-90. AVO personnel installed two new seismic instruments near Redoubt over the past week, and improved signals coming in from the Redoubt seismic network at AVO's facility in Homer. Staff continue to monitor the volcano 24 hours a day. We will issue further information as it becomes available.

January 2009 Updates

Sunday, January 25, 2009 2:09 02:09:57 AM AKDT
Friday, January 23, 2009 12:21 12:21:46 PM AKDT
Friday, January 16, 2009 12:54 12:54:20 PM AKDT
Friday, January 9, 2009 1:35 01:35:42 PM AKDT
Friday, January 2, 2009 1:48 01:48:39 PM AKDT

December 2008 Updates

Friday, December 26, 2008 1:52 01:52:28 PM AKDT
Friday, December 19, 2008 12:03 12:03:58 PM AKDT
Friday, December 12, 2008 9:25 09:25:41 AM AKDT
Friday, December 5, 2008 11:47 11:47:05 AM AKDT

November 2008 Updates

Friday, November 28, 2008 12:44 12:44:30 PM AKDT
Friday, November 21, 2008 12:07 12:07:18 PM AKDT
Friday, November 14, 2008 12:05 12:05:29 PM AKDT

Seismic activity this week remained at low levels. Satellite views of the volcano were clear to partly cloudy with no activity observed. AVO staff made observations and began work to install additional geophysical equipment and a web camera on the volcano last weekend. New FLIR thermal-infrared camera images from last Friday document elevated temperatures in the areas of bare rock and disrupted ice near the summit crater and in a collapse hole within the Drift Glacier. Closer inspection of the summit fumaroles was not possible due to poor weather.

Friday, November 7, 2008 11:55 11:55:45 AM AKDT

On Wednesday, November 5, 2008, AVO raised the Aviation Color Code to YELLOW and the Volcano Alert Level to ADVISORY owing to the several month long detection of potentially significant changes in gas emission and heat output from Redoubt Volcano. These changes are a departure from long-observed background activity. The remainder of the week seismic activity remained at low levels and satellite views of the volcano were partly cloudy with no activity observed. AVO staff began work to install additional geophysical equipment and a web camera on the volcano.

Wednesday, November 5, 2008 2:52 02:52:26 PM AKDT

Over the past several months, AVO has detected potentially significant changes in gas emission and heat output from Redoubt Volcano. These changes are a departure from long-observed background activity, and therefore, AVO is raising the Aviation Color Code to YELLOW and the Volcano Alert Level to ADVISORY. There is no indication that an eruption is imminent or even certain. AVO is monitoring Redoubt closely and is making plans to install additional equipment on the volcano in the next several weeks.

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Redoubt Activity - Color Code ORANGE : Alert Level WATCH

Local time: May 09, 2009 1340 AKDT (May 09, 2009 2140 UTC)