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2004 December 17

USGS Update 2004-Dec-17 09:50

Potential ash hazards: Wind forecasts from the National Oceanic and Atmospheric Administration (NOAA), coupled with eruption models, show that ash clouds that rise above the crater rim today would drift east-southeastward.

Recent observations: We got clear views of the crater mid-day yesterday during a thermal-imaging flight. The new dome has noticeably broadened and the prominent fracture system along its top continues to widen. Hot cracks emit ash intermittently. During the night of December 15 (Wednesday) ash emitted from the east side of the dome formed a cloud that swept down the east arm of the glacier and over east side of the old lava dome, leaving a dark smear of ash on the snow on its north face. This smear is visible on the USFS VolcanoCam. The flow was relatively cool as it did not melt much snow. We were also able to repair an important radio-telemetry site that was severely damaged during the recent windstorm and do other needed maintenance. Owing to a late start caused by lingering fog in the metro area, we were not able to fit in a gas-sensing flight. That flight will begin shortly today. This morning the volcano is emitting a vapor plume that is drifting over the southeast crater rim. Four earthquakes of about magnitude 3 occurred overnight amidst the ongoing pattern of frequent smaller earthquakes. Swarms of similar-sized events have occurred on several occasions during the past month.