(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued:(20111103/1916Z)
(3) Volcano:Cleveland (CAVW# 1101-24-)
(4) Current Color Code:YELLOW
(5) Previous Color Code:orange
(6) Source:Alaska Volcano Observatory
(7) Notice Number:2011/A6
(8) Volcano Location:N 52 deg 49 min W 169 deg 56 min
(9) Area:Aleutians Alaska
(10) Summit Elevation:5676 ft (1730 m)
(11) Volcanic Activity Summary:Satellite observations of Cleveland Volcano over the past three weeks have consistently indicated that the lava dome in the summit crater has not significantly changed in size indicating that the slow eruption of lava may have paused or stopped. Thermal features also observed in satellite data indicate that the lava dome remains hot. When atmospheric conditions permit, thermal features at the summit will be detected until the lava dome cools. Based on satellite observations indicating no significant change in the size of the lava dome, and no reports of explosive activity or ash emission, AVO is lowering the Aviation Color Code and Volcano Alert Level to YELLOW/ADVISORY.

It is possible for effusion of lava to resume at any time and continued production of lava in the summit crater could result in lava flows that overtop the crater rim and flow down the flanks of the volcano. Such lava flows could collapse and produce avalanches of hot debris that reach the sea and may be accompanied by small ash clouds. A sudden explosion and ash cloud exceeding 20,000 feet above sea level could also occur. Such explosions may go undetected in satellite imagery for hours. However, in cooperation with the University of Washington, AVO has implemented a lightning alarm system that may detect significant ash-producing events within minutes of onset. If a large explosive event occurs, seismic signals may be recorded on AVO seismic networks at nearby volcanoes; however, there is no real-time seismic network on Mt. Cleveland.

Additional information on Cleveland Volcano and the current activity may be found at this link:
http://www.avo.alaska.edu/activity/Cleveland.php

(12) Volcanic cloud height:Unknown
(13) Other volcanic cloud information:Unknown
(14) Contacts:John Power, Scientist-in-Charge, USGS
jpower@usgs.gov (907) 786-7497

Steve McNutt, Coordinating Scientist, UAF
steve@giseis.alaska.edu (907) 474-7131
(15) Next Notice:A new VONA will be issued if conditions change significantly or alert levels are modified. While a VONA is in effect, regularly scheduled updates are posted at
http://www.avo.alaska.edu