New Report Ranks The Most Threatening US Volcanoes

When it comes to ranking the threat levels of volcanoes, one size does not fit all. All volcanoes pose a risk in some way or another, but those risks depend on a variety of factors including (but not limited to) distance to human settlements, pyroclastic flows, and infrastructure downstream and downwind.

For the first time since 2005, the US Geological Survey has updated its assessment of the most threatening volcanoes based on 24 hazard factors. The 2018 update uses new resources to determine which volcanic systems should be added or removed. Of a total of 161 volcanoes, 12 volcanoes have moved up in threat level and 20 others have dropped.

All of the 18 volcanoes designated as a “very high threat” are found on the West Coast, 11 of which are in Washington, Oregon, or California where "explosive and often snow- and ice-covered edifices can project hazards long distances to densely populated and highly developed areas," according to the report.

Five of the 18 most dangerous volcanoes are in Alaska near important population centers, economic infrastructure, or below busy air traffic corridors. The remaining two volcanoes are on the Hawaiian Islands, where population and developed areas are built along the flanks of active volcanoes.

Active volcanoes are those that have erupted during the Holocene (the last 11,700 years) or those in long-lived Caldera systems like Yellowstone. Home to 10 percent of the world’s known volcanoes, the US is one of Earth’s most volcanically active countries. From Arctic Alaska to tropical American Samoa, the nation has seen some of the most dramatic eruptions in modern history, including the lava flows expelled earlier this year by Hawaii’s Kilauea and the engine-halting ash from the Redoubt Volcano in Alaska to the devastating 1980 eruption of Mount Saint Helens.

The threat assessment places volcanoes in the US into five threat categories: very low, low, moderate, high, and very high.

“Within all five threat categories there are changes in relative rankings of volcanoes, and in a few cases, volcanoes moved between categories owing to changes in our understanding of their hazard, unrest, and exposure factors,” reads the report.

It's important to note that this report doesn't mention which volcanoes will erupt next or how well they are monitored, but instead ranks the potential of these volcanoes to cause damage.

Now, without further ado, the “very high threat” volcanoes are:

1. Kilauea, Hawaii

Fissure 8 lava flows in an open channel all the way to the ocean. Kapoho Crater is the vegetated hill on the right side of the photograph. Ocean entry plume can be seen in the distance. USGS

2. Mount St. Helens, Washington

Mount St. Helens erupted on May 18, 1980, and became the epicenter of an earthquake measuring 5.1 on the Richter scale. CDC/Wikimedia Commons

3. Mount Rainier, Washington
Seattle skyline shows Mt. Rainier in the background. Andrew Bondarchuck/Shutterstock
4. Redoubt Volcano, Alaska

Redoubt Volcano erupting in Alaska's Cook Inlet. Lone Wolf Photo/Shutterstock
5. Mount Shasta, California

View of Mt. Shasta from Interstate 5. hubert999/Shutterstock
6. Mount Hood, Oregon

Mount Hood can be seen in the background of Portland, Oregon. Kevin Bermingham/Shutterstock
7. Three Sisters, Oregon

View of Bend and part of the Cascade Mountain Range in central Oregon. Jess Kraft/Shutterstock
8. Akutan Island, Alaska

Houses on Akutan Island in Alaska. Daniel Briem/Shutterstock

9. Makushin Volcano, Alaska

Makushin Volcano smoking away on the west end of Unalaska Island. NOAA/Wikimedia Commons
10. Mount Spurr, Alaska

Aerial view of a 1992 eruption column from the Cater Peak vent on Mount Spurr. USGS/Wikimedia Commons
11. Lassen Volcanic Center, California
Bumpass Hell in Lassen Volcanic National Park. Pierre LeClerc/Shutterstock
12. Augustine Volcano, Alaska
Augustine volcano during a 2006 eruption. Alaska Volcano Observatory
13. Newberry Volcano, Oregon
The edge of a volcanic obsidian flow meets undisturbed forest. Lindsay Snow/Shutterstock
14. Mount Baker, Washington

Mount Baker as seen behind the Vancouver skyline. Saulty72/Shutterstock
15. Glacier Peak, Washington

Glacier Peak in Washington. Galyna Andrushko/Shutterstock
16. Mauna Loa, Hawaii

Lava flow at Mauna Loa. Alohaisland/Shutterstock
17. Crater Lake, Oregon

Crater Lake in Oregon. Stas Moroz/Shutterstock
18. Long Valley Caldera, California

The 6-kilometer (3.8-mile) basin is home to approximately 90 geysers and geothermal hot springs. Milevshi/Shutterstock