USGS Update 2005-May-03 10:30

Views taken in last week

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 eastward early in the day and northeastward later.

Recent observations: The volcano is clear this morning and we hope to make thermal-imaging and visual observations and resurvey some targets that were placed on the new lava dome last month. Rates of seismicity and ground deformation remain unchanged as lava-dome growth continues. We discovered an error in the update of April 23 that gave the March 10 volume of the new lava dome and area of uplift as 62 million cubic yards. The correct volume on that date was 58 million cubic yards (45 million cubic meters). The highest point on the new dome was about 7675 feet, which was more than 500 feet above the top of the old lava dome. Since then, the dome has gone through a period of disintegration and spreading as it continues to increase in volume, so the high point is probably now somewhat lower.

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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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