Treesearch
Mount St. Helens 30 years later: a landscape reconfigured.
| Authors: | Rhonda Mazza |
| Year: | 2010 |
| Type: | Science Update |
| Station: | Pacific Northwest Research Station |
| Source: | Science Update 19. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station. 11 p. |
Download (PDF 3.49 MB): https://research.fs.usda.gov/download/treesearch/34657.pdf
Abstract
On May 18, 1980, after two months of tremors, Mount St. Helens erupted spectacularly and profoundly changed a vast area surrounding the volcano. The north slope of the mountain catastrophically failed, forming the largest landslide witnessed in modern times. The largest lobe of this debris avalanche raced 14 miles down the Toutle River valley, filling it to an average depth of 150 feet. The landslide unleashed hurricane-force winds of hot gases filled with rocks that toppled 143 square miles of trees. Farther away, 42 square miles of trees were killed by the heat of the blast but left standing—ghostly sentinels still watching 30 years later.