Government scientists have classified 18 US volcanoes as "very high threat" because of what's been happening inside them and how close they are to people. The US Geological Survey has updated its volcano threat assessments for the first time since 2005, per the AP, and the danger list is topped by Hawaii's Kilauea, which has been erupting this year. The others in the top five are Mount St. Helens and Mount Rainier in Washington, Alaska's Redoubt volcano, and California's Mount Shasta. "The US is one of the most active countries in the world when it comes to volcanic activity," says Concord University volcano expert Janine Krippner, noting there have been 120 eruptions in US volcanoes since 1980. Eleven of the 18 very-high-threat volcanoes are in Oregon, Washington, and California.
Government scientists use two dozen factors to compute an overall threat score for each of the 161 young active volcanoes in the nation, including the type of volcano, how recently it has been active, and how frequently it erupts. They're then sorted into five threat levels. The biggest US city in a hazard area for a very-high-threat volcano: likely Hilo, Hawaii, in the shadow of Mauna Loa, per volcanologist John Ewert, the report's chief author. Of the highest-threat volcanoes, Washington's Mount Rainier has the highest number of people—about 300,000—in the downstream hazard zone. The rest of the "Big 18": Oregon's Mount Hood, Three Sisters, Newberry, and Crater Lake; Alaska's Akutan Island, Makushin, Mount Spurr, and Augustine; California's Lassen and Long Valley; Washington's Mount Baker and Glacier Peak; and Hawaii's Mauna Loa.
(Read more volcanoes