Cascade Range Current Update |
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U.S. Geological Survey, Vancouver, Washington
University of Washington, Pacific Northwest Seismic Network, Seattle, Washington
MOUNT ST. HELENS UPDATE
Current Volcanic- Alert Level WATCH: Aviation Color Code ORANGE :
Growth of the new lava dome inside the crater of Mount St. Helens
continues, accompanied by low rates of seismicity, low emissions of
steam and volcanic gases, and minor production of ash. During such
eruptions, changes in the level of activity can occur over days to
months. The eruption could intensify suddenly or with little warning
and produce explosions that cause hazardous conditions within several
miles of the crater and farther downwind. Small lahars could suddenly
descend the Toutle River if triggered by heavy rain or by interaction
of hot rocks with snow and ice. These lahars pose a negligible hazard
below the Sediment Retention Structure (SRS) but could pose a hazard
along the river channel upstream.
Potential ash hazards: Wind forecasts from the National Oceanic and
Atmospheric Administration (NOAA), coupled with eruption models, show
that any ash clouds rising above the crater rim today would drift to
the east with a shift to southeast late in the day.
Potential ash hazards to aviation: Under current eruptive conditions,
small, short-lived explosions may produce ash clouds that exceed
30,000 feet in altitude. Ash from such events can travel 100 miles or
more downwind.
Recent observations: Snow and unsettled weather preclude visual
observation of the crater today. Seismic data indicate the eruption
continues as slow extrusion accompanied by small earthquakes.
Seismicity over the past 24 hours is unchanged from recent levels.
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.
For additional information, background, images, and other
graphics:
For seismic information:
For a definition of alert levels:
For a webcam view of the volcano:
Telephone recordings with the latest update on Mount St. Helens
and phone contacts for additional information can be heard by
calling:
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.
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Link to:
[USGS Volcano Hazards Program Updates Page (includes Alaska, Hawaii, and Long Valley)] ...
[University of Washington's Pacific Northwest Earthquake Information (current seismicity)]
