Clearwater Overlook

Clearwater Drainage, 1982
USGS Photo by Lyn Topinka, April 26, 1982

To the north is part of the zone devastated by the May 18, 1980, blast. On the east wall of Clearwater Creek valley is the east edge of the devastated zone, about 10 miles from the summit. Most of the fallen or damaged timber has been salvaged.

-- Excerpts from: Doukas, 1990, Road Guide to Volcanic Deposits of Mount St. Helens and Vicinity, Washington: USGS Bulletin 1859, 53p.

Clearwater Creek Valley

The broad, U-shaped valley of Clearwater Creek was carved by a glacier of Hayden Creek age (about 140,000 years ago) and possibly by an earilier glacier. On May 18, 1980, the hot blast moved into the upper reaches of the valley, destroying most of the forest (much of it recently logged). Slope failures, mostly debris slides, were common during the next few years in this and nearby valleys affected by the blast. Experimental forest plots were set up to investigate the causes of the slope failures. One reason was that trees died after the 1980 eruption and their roots stopped providing cohesive strength to the soil.

-- Excerpts from: Pringle, 1993, Roadside Geology of Mount St. Helens National Volcanic Monument and Vicinity: Washington Department of Natural Resources, Division of Geology and Earth Resources Information Circular 88