Magma build-up under Mount St. Helens ‘normal’

the Mount St. Helens crater is covered in wildflowers.
Years after the 1980 eruption, the Pumice Plain north of the Mount St. Helens crater is covered in wildflowers. Photo: P. Frenzen/USDA Forest Service (2004).

Although magma is rising again deep inside the Mount St. Helens volcano, geologists say an eruption is not likely anytime soon. The magma reservoir beneath Mount St. Helens has been slowly re-pressurizing since 2008. The volcano erupted violently on May 18, 1980, killing 57 people and altering the surrounding landscape.

Seismologists with the Cascades Volcano Observatory say that the volcano could accumulate pressure inside for a long time before there would be an eruption. As with the 1980 blast, the mountain would provide many indications if it were about to erupt. All the same, it’s wise for those of us in Washington State — home to five active volcanoes — to be aware of these rare-but-devastating events. Here are the latest on alert levels for Cascade Range volcanoes from the U.S. Geological Survey Cascades Volcano Observatory.

Consider these volcano facts:

  • Washington’s five large volcanic cones (Mount Baker, Glacier Peak, Mount Rainier, Mount Adams, and Mount St. Helens) are presently not erupting, but are considered active because of the recentness of eruptions, and the long-term presence of earthquakes and thermal features.
  • During the last 4,000 years, eruptions at Cascade volcanoes—from Washington State to northern California—happened at an average of once or twice a century, with individual eruptions lasting for months, years, and even decades.
  • Seven volcanoes in the Cascade Range have erupted since 1776; four of these eruptions would have caused substantial damage and loss of life if they occurred today
  • As the population increases in the Pacific Northwest, areas near volcanoes — especially Mount Rainier and Mount Hood — are being developed and recreational usage is expanding, putting more people and property at risk from volcanic activity.

DNR and its Division of Geology and Earth Resources work with the Washington State Emergency Management Division, the USGS and other agencies to map, monitor and educate the public, governments and others about geologic hazards, including volcanoes.