Cascade Range Current Update

Friday, February 22, 2008 09:28 PST (Friday, February 22, 2008 17:28 UTC)
MOUNT ST. HELENS WEEKLY UPDATE
Volcanic-Alert Level ADVISORY - Aviation Color Code YELLOW:

SUMMARY:

Growth of the new lava dome inside the crater of Mount St. Helens, which began in October 2004, appears to have paused beginning in late January 2008. This change may only reflect a temporary pause; therefore, the situation continues to be closely monitored for possible renewed lava extrusion or other activity. The new lava dome remains hot in places and capable of producing hot avalanches or small steam explosions that could cause hazardous conditions in and around the crater. Sudden melting of snow and ice could send small lahars onto the Pumice Plain and perhaps down the Toutle River as far as the Sediment Retention Structure (SRS). Ash clouds from explosions could affect aircraft.

RECENT OBSERVATIONS:

Seismicity and ground-tilt remain at very low levels and examination of recent photographs from a remote camera on the crater rim confirms no recent detectable growth of the lava dome.

The U.S. Geological Survey and the University of Washington continue to monitor the situation closely and will issue additional updates and changes in alert level as warranted.

INFORMATION:

For additional information, background, images, and other graphics:
http://vulcan.wr.usgs.gov/Volcanoes/MSH/Eruption04/

For seismic information:
http://www.pnsn.org/HELENS/welcome.html

For a definition of alert levels:
http://vulcan.wr.usgs.gov/Volcanoes/Cascades/CurrentActivity/volcano_warning_scheme.html

For a webcam view of the volcano:
http://www.fs.fed.us/gpnf/volcanocams/msh/

Telephone recordings with the latest update on Mount St. Helens and phone contacts for additional information can be heard by calling:
Media (360) 891-5180

OTHER CASCADE VOLCANOES

All other volcanoes in the Cascade Range are all at normal levels of background seismicity. These include Mount Baker, Glacier Peak, Mount Rainier, and Mount Adams in Washington State; Mount Hood, Mount Jefferson, Three Sisters, Newberry, and Crater Lake, in Oregon; and Medicine Lake, Mount Shasta, and Lassen Peak in northern California.

USGS Cascades Volcano Observatory, the Pacific Northwest Seismograph Network at the University of Washington, and the USGS Northern California Seismic Network and Volcano Hazards Team in Menlo Park, California, monitor the major volcanoes in the Cascade Range of northern California, Oregon, and Washington.



Past Updates

Mount St. Helens Current Eruption Menu