USGS Update 2005-Nov-19 08:50

Potential ash hazards: Wind forecasts from the National Oceanic and Atmospheric Administration (NOAA), coupled with eruption models, show that any ash clouds that rise above the crater rim today would drift northwestward to northward at all elevations early, remain in that trajectory at low elevations all day, but shift to a northeastward trajectory at high elevations later in the day.

Recent observations: Over the past few days, crews successfully installed a tiltmeter in the crater and new cameras at the crater mouth and on the east crater rim, repaired and replaced seismometers and installed a new GPS on the new lava dome, repaired communications linkages, and collected new thermal imagery. Views from various vantage points show clearly that the active part of the new lava dome has risen several tens of meters since latter October, demonstrating without doubt that dome growth continues. This growth continues to be accompanied by a remarkably regular and repetitive series of small earthquakes. Clear conditions at the volcano this morning reveal a vapor plume emitting from the area of active growth.

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Standard USGS Update

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, episodic changes in the level of activity can occur over days to months. The eruption could also 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 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.

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.

My intent with this page is to provide a clearning house for links to the current activity at Mt.St.Helens. Please send me any links of interest that you may come across, whether for permanent sites or for news reports. I'm not going to be able to do this all alone and all help will be appreciated.

(Disclaimer— I have no association with anyone or any organization, and speak only for myself. Links and quotes are provided for information only.)

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