Mount St. Helens Volcano |
Northwest Legends |
Baron St. Helens |
Early Documentation |
"On the 23rd day of the preceding November, St. Helens had scattered its ashes, like a light fall of snow, over the Dalles of the Columbia."
First Ascent |
Hydrologic Setting |
Eruptive History |
Mount St. Helens remains a potentially active and dangerous volcano, even though it is now (1995) quiescent. In the last 515 years, it is known to have produced 4 major explosive eruptions (each with at least 1 cubic kilometer of eruption deposits) and dozens of lesser eruptions. Two of the major eruptions were separated by only 2 years. One of those, in 1480 A.D., was about 5 times larger than the May 18, 1980 eruption, and even larger eruptions are known to have occurred during Mount St. Helens' brief but very active 50,000-year lifetime. Following the most recent major eruption, on May 18, 1980, there were 5 smaller explosive eruptions over a period of 5 months. Thereafter, a series of 16 dome-building eruptions through October 1986 constructed the new, 270-meter- (880-feet) high, lava dome in the crater formed by the May 18, 1980 eruption.
May 18, 1980 |
Lava Dome |
Volcano and Hydrologic Monitoring |
Mount St. Helens National Volcanic Monument |
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