2005-07-22

 

USGS Update 2005-Jul-22 10:15

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 north-northeastward early in the day and eastward to east-southeastward later.

Recent observations: Brief glimpses of the new lava dome from the Sugar Bowl DomeCam early this morning show a vapor plume rising above the growing lava dome. Overnight rain has settled the dust that was blowing around the crater yesterday and has created atmospheric conditions favorable for a visible vapor plume. Numerous rockfalls occurred overnight as revealed by flashes of light on the VolcanoCam. Analysis of a digital elevation model created from aerial photographs taken on June 15 shows that the volume of the new lava dome was about 54 million cubic meters (70 million cubic yards), or about 60% of the volume of the lava dome that grew in the crater from 1980 to 1986. The rate of addition of lava to the dome from mid-May to mid-June remained at about 1.5 cubic meters (2 cubic yards) per second. The high point of the lava dome (the actively growing spine) on June 15 was 2335 meters (7660 feet), but it is currently lower than that owing to the recent large rockfalls from the spine.





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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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