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The U.S. Geological Survey has updated its list of the nation's most-threatening volcanoes, and five of the top 10 are in the Pacific Northwest's Cascade range.

Using a metric of 24 factors -- including capacity to eject debris, proximity to population centers and potential impact to air traffic -- researchers dubbed Hawaii's Kilauea the volcano that poses the biggest threat.

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Lava from Kilauea volcano erupts in the Leilani Estates neighborhood near Pahoa, Hawaii on on July 14, 2018. (U.S. Geological Survey via AP)

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Second and third went to Mount Rainier and Mount St. Helens, respectively. Mount Shasta, in northern California, Mount Hood and the Three Sisters came in fifth, sixth and seventh on the list.

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The summit of Mount Rainier, blanketed with cloud cover, as seen from the top of Mount St. Helens. (Steve Ringman/Seattle Times/TNS)

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North Sister and Middle Sister with Collier Glacier. (Terry Richard/The Oregonian)

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The top rankings did not change since the last time the agency conducted the assessment in 2005.

"It's not a reason to panic," said Adam Kent, a geology professor at Oregon State University. "But it is certainly a reason to stay vigilant."

The threat assessment does not indicate how likely a volcano is to erupt.

"The threat ranking is not an indication of which volcano will erupt next," the geological survey said in a statement. "Rather, it is an indicator of the potential severity of impacts that could result from future eruptions at any given volcano."

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(Mark Graves/The Oregonian)

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In total, 11 of the 18 volcanoes listed under the "very high threat" category were in Oregon, Washington or California. Many of those volcanoes are located "where explosive and often snow- and ice-covered edifices can project hazards long distances to densely populated and highly developed areas," the agency said in a

.

The other Oregon volcanoes in the top category were Crater Lake and Newberry Volcano, which was upgraded since the last assessment in 2005.

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A view of Wizard Island from Discovery Point on Rim Drive in Crater Lake National Park. (Jamie Hale/The Oregonian)

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A big part of the threats posed by volcanoes in the Cascades, according to Kent, is the interaction of heat with snow and ice. When a volcano erupts on a snow-covered peak, all that frozen water melts quickly and can cause massive, quick-moving flows called lahars.

Those lahars can travel great distances on existing river systems. The last time Mount Hood saw a major eruption, in the 1790s, lahars traveled down the Sandy River and reached the Columbia.

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Rescuers monitor the lahar devastated area near where the Las Lajas bridge used to be, after the eruption of the Volcan de Fuego, or Volcano of Fire, in El Rodeo, Guatemala, Thursday, June 14, 2018. (Luis Soto/AP)

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Oxbow Park, southeast of Troutdale, is still covered with material carried in by a lahar more than 200 years ago, Kent said.

Several Oregon volcanoes were dropped from the list, which ranges from "very high threat" to "very low." Mount Washington, Lava Mountain, Four Craters Lava Field and Jackies Butte all fell off the bottom of the list after updated research showed they no longer posed even a very low threat.

The U.S. is home to 161 young, active volcanoes, more than any other country in the world. Since 1980, the country has seen 120 eruptions and 52 episodes of notable volcanic unrest at 44 U.S. volcanoes, with the 1980 eruption of Mount St. Helens being one of the most notable.

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-- Kale Williams

kwilliams@oregonian.com

503-294-4048