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USGS Updates National Volcanic Threat Assessments for 1st Time Since 2005

Mount Rainier in Washington state sits in the Cascade volcanic arc.

Mount Rainier in Washington state sits in the Cascade volcanic arc. Michael Grass / Route Fifty


Connecting state and local government leaders

18 U.S. volcanoes are now classified as posing “very high threats.”

The U.S. Geological Survey has updated its list of U.S. volcanoes that pose a “very high” threat “due to what’s been happening inside them and how close they are to people,” as the Associated Press reported Thursday. It’s the first update to USGS National Volcanic Threat Assessment since 2005.

Eleven of the 18 very high threat volcanoes are in California, Oregon and Washington state; five are in Alaska, and pose major risks to air routes between the U.S. and Asia.

Mount Rainier, southeast of Tacoma, Washington, has the highest number of people living in areas vulnerable to volcanic debris flows.  

Volcanic hazards from Mount Rainier in Washington state (via USGS)

Volcanic threats in the Pacific Northwest (via USGS)

Also on the very high threat list are Mauna Loa and Kilauea on Hawaii’s Big Island; Redoubt volcano southwest of Anchorage, Alaska; Mount Hood near Portland, Oregon; the Three Sisters and Newberry volcanoes near Bend, Oregon; Mount Shasta, Long Valley Caldera and Lassen Peak in northern California; and in Washington state, Mount St. Helens, Mount Baker and Glacier Peak in Washington state.

Volcanic threats in California and Nevada (via USGS)

Three volcanoes were added to the USGS assessment as active or potentially active that were not included in the 2005 assessment: The Salton Buttes in nouthern California; Soda Lakes in Nevada; and Red Hill-Quemado volcanic field in New Mexico. Fourteen volcanoes were dropped from the active or potentially active list.

Michael Grass is Executive Editor of Government Executive’s Route FIfty and is based in Seattle.

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