Cascade Volcanoes

Mount St. Helens NVM
Washington

Lassen Volcanic NP
California


Prior to its most recent eruption, the conical shape of Mount Saint Helens did not bear the marks of glaciers, which indicated that it was active more recently than other Cascade volcanoes, such as Mount Rainier. Mount Saint Helens erupted violently in May 1980, when a landslide on the north flank allowed the pent-up pressure of steam in the magma rising within the volcano to escape. The montane forest and riparian communities destroyed in the surrounding blast zone are slowly beginning to recover. Trees in these forests live for centuries, so the more than 25 years that have elapsed since the eruption represent a relatively short amount of time in the life of a forest community. Those of us with lifespans measured in decades tend to be a little impatient with nature. The low vegetation now growing in the blast zone benefits wildlife, such as the 2 groups of elk that we saw grazing in July 2000 in the valley situated between us and the volcano in the photograph below on the left.

Image of VolcanoImage of Blast Zone
Mount Saint Helens Crater (left) and Surrounding Blast Zone (right), Washington
Photographs by Mark Eberle, August 1998

Prior to the eruption of Mount Saint Helens, the most recent volcanic eruptions in the Cascades occurred from 1914 through 1917 at Lassen Peak in northern California. The most explosive of these eruptions occurred on 22 May 1915. Current hydrothermal features in Lassen Volcanic National Park include fumaroles (vents of steam and volcanic gases), mudpots, and hot springs. Lassen Volcanic National Park and its active hydrothermal features are being considered as an addition to the fieldtrip in 2010.

Separation line
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