From: Jon J Major

U.S. Geological Survey, Vancouver, Washington
University of Washington, Pacific Northwest Seismograph Network, Seattle,
Washington

Mount St. Helens Information Statement,

Tuesday, March 8, 2005, 6:00 P.M. PST (0200 UTC March 9, 2005)
A small explosive event at Mount St. Helens volcano began at approximately
5:25 p.m. PST. Pilot reports indicate that the resulting steam-and-ash
plume reached an altitude of about 36,000 feet above sea level within a
few minutes and drifted downwind to the east-northeast. The principal
event lasted about 30 minutes with intensity gradually declining
throughout. The USGS Cascades Volcano Observatory lost radio signals from
three monitoring stations in the crater soon after the event started. The
cause of the outage won't be known until scientists can visit the crater
tomorrow to assess the situation, weather permitting. The event followed a
few hours of slightly increased earthquake activity that was noted but not
interpreted as precursory activity. There were no other indications of an
imminent change in activity.

The current hazard assessment for the ongoing eruption mentions the
possibility of such events occurring without warning, and the assessment
remains unchanged. 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.