U.S. Geological Survey
March 8, 2005
The principal event lasted about 30 minutes, with intensity gradually declining throughout. The resulting plume was mostly white or light colored as viewed in the Pacific Northwest sunset, which is the basis for our preliminary assessment that steam was the predominant component. Even so, light dustings of ash are expected on the flanks of the volcano and are possible as far away as central Washington.
The eruption was photographed by many residents in the Portland-Vancouver metropolitan area. Images on a ten-minute sequence were captured by the web cam at the U.S. Forest Service's Johnston Ridge Observatory, 8.5 kilometers (5.2 miles) north of the volcano. We've annotated one of those images from late in the sequence, for the benefit of readers who browse to the U.S. Forest Service website.