Cascade Range Current Updates
December 2009

CASCADE RANGE VOLCANOES
Current Volcano Alert Level: NORMAL
Current Aviation Color Code: GREEN

Activity Update: All volcanoes in the Cascade Range are at normal levels of background seismicity. These include Mount Baker, Glacier Peak, Mount Rainier, Mount St. Helens, and Mount Adams in Washington State; Mount Hood, Mount Jefferson, Three Sisters, Newberry Volcano, and Crater Lake, in Oregon; and Medicine Lake volcano, Mount Shasta, and Lassen Peak in northern California. Mount St. Helens has been at Volcano Alert Level NORMAL (Aviation Color Code GREEN) since July 10, 2008.

Recent Observations: Activity at Cascades volcanoes remains at normal levels this week. A short-lived burst of micro earthquakes (M~0.5) occurred at Mount Rainier on November 29, located near Camp Muir. On December 1, two small earthquakes (largest M1.2) occurred at Mount Hood, located near the summit. On December 2, field crews visited Mount St. Helens to conduct routine equipment maintenance and to collect data on channel geometry along the North Fork Toutle River.

CASCADE RANGE VOLCANOES
Current Volcano Alert Level: NORMAL
Current Aviation Color Code: GREEN

Activity Update: All volcanoes in the Cascade Range are at normal levels of background seismicity. These include Mount Baker, Glacier Peak, Mount Rainier, Mount St. Helens, and Mount Adams in Washington State; Mount Hood, Mount Jefferson, Three Sisters, Newberry Volcano, and Crater Lake, in Oregon; and Medicine Lake volcano, Mount Shasta, and Lassen Peak in northern California. Mount St. Helens has been at Volcano Alert Level NORMAL (Aviation Color Code GREEN) since July 10, 2008.

Recent Observations: The only Cascade Range activity of note this week was a handful of small shallow earthquakes at Mount Rainier occurring late Thursday evening into Friday morning (12/10-12/11). The largest event (M 2.3) occurred at 21:30 PST on 12/10. Preliminary locations from the PNSN indicate that the shallow earthquakes were located ~1 mile northeast of the summit, in the vicinity of a larger earthquake swarm that occurred September 20-23, 2009. This seismicity is considered to be within the realm of normal activity at Mount Rainier.

CASCADE RANGE VOLCANOES
Current Volcano Alert Level: NORMAL
Current Aviation Color Code: GREEN

Activity Update: All volcanoes in the Cascade Range are at normal levels of background seismicity. These include Mount Baker, Glacier Peak, Mount Rainier, Mount St. Helens, and Mount Adams in Washington State; Mount Hood, Mount Jefferson, Three Sisters, Newberry Volcano, and Crater Lake, in Oregon; and Medicine Lake volcano, Mount Shasta, and Lassen Peak in northern California. Mount St. Helens has been at Volcano Alert Level NORMAL (Aviation Color Code GREEN) since July 10, 2008.

Recent Observations: The seismicity for the Cascade Range volcanoes is at background levels. Last week's handful of small, shallow earthquakes at Mount Rainier tapered off on December 12.

CASCADE RANGE VOLCANOES
Current Volcano Alert Level: NORMAL
Current Aviation Color Code: GREEN

Activity Update: All volcanoes in the Cascade Range are at normal levels of background seismicity. These include Mount Baker, Glacier Peak, Mount Rainier, Mount St. Helens, and Mount Adams in Washington State; Mount Hood, Mount Jefferson, Three Sisters, Newberry Volcano, and Crater Lake, in Oregon; and Medicine Lake volcano, Mount Shasta, and Lassen Peak in northern California. Mount St. Helens has been at Volcano Alert Level NORMAL (Aviation Color Code GREEN) since July 10, 2008.

Recent Observations: The seismicity for the Cascade Range volcanoes is at background levels. There are no significant new observations to report.