Washington’s most dangerous volcanoes, mapped (2024)

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Seattle is so fixated on our looming major earthquakes that it can be easy to overlook the major drawback of life along the Cascadia subduction zone: volcanoes.

The latest volcano threat assessment from the United States Geological Survey (USGS) has some sobering news for Washington State: We have two out of the three highest-threat volcanoes in the country, with Mount Rainier and Mount St. Helens behind only Hawaii’s Kīlauea—which has been venting since a major 1983 eruption but had a major event earlier this year.

Our last eruption was Mount St. Helens in 1980, so it’s usually at the forefront of our volcano awareness—and we sometimes forget that some of our most beloved landmarks like Mount Rainier and Mount Baker are also, in fact, volcanoes that can erupt. Fortunately, the Seattle Times reported, our volcanoes are “cold” enough that we should have plenty of warning to get out of their way, and the USGS carefully monitors all of them. But it doesn’t make our sheer concentration of very-high-threat volcanoes any less jarring.

We’ve mapped out our most dangerous volcanoes, according to the latest assessment, because it turns out the Cascades are kind of a nightmare.

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Distance to Seattle: 185 miles

Last eruption: Last major eruption on May 18, 1980

Danger level: Very high

“Prior to 1980, Mount St. Helens had the shape of a conical, youthful volcano sometimes referred to as the Mount Fuji of America,” notes the USGS. While the 1980 incident, which lasted through 1986, makes up the major eruption that people alive today in the Northwest can remember, it’s had a couple of minor eruptions since then, including a minor eruptive period between 2004 and 2008.

In 1980, volcanic ash reached far enough to the east to cause complete darkness 250 miles to the east in Spokane and a major lahar flowed down into the Cowlitz River, reaching its peak size about 50 miles downstream from the volcano. Lahars destroyed more than 200 homes and more than 185 miles worth of road. There’s one town in the immediate blast zone of the volcano—Cougar—that could experience the more immediate effects like rock fall. Lahar risk stretches down the Toutle and Cowlitz rivers.

The USGS considers Mount St. Helens to be the third highest-risk volcano in the country.

Distance to Seattle: 60 miles

Last eruption: Possible minor eruption in 1894; last major eruption 1,000 years ago.

Danger level: Very high

Seattle’s closest active volcano, aka Tahoma, the mountain of “the mountain is out,” is the third-most-dangerous volcano in the country, according to the USGS assessment. could send lahars south down the Cowlitz River; north in the river basins of the Puyallup, White River, and Carbon River; and west down the Nisqually. Risk spreads out to Tacoma, the Muckleshoot and Nisqually reservations, and down to Randle.

Distance to Seattle: 130 miles

Last eruption: 1880 or 1843 (last major eruption 6,700 years ago)

Danger level: Very high

Lahars—or volcanic mudflows—from Baker’s last big eruption left deposits in the Nooksack Valley, and little eruptions were witnessed throughout the 1800s. Its ground hazard zones flow out to Ferndale to the northwest and and down into the Skagit Valley to the southwest; the USGS doesn’t consider tephra, or falling ash and rocks, to be a major concern.

Distance to Seattle: 70 miles

Last eruption: 1700

Danger level: Very high

Glacier’s lahar risk zones stretch down the Skagit River and the north fork of the Stillaguamish river, out to Stanwood, La Conner, and as far out as Samish Bay. The USGS notes that this volcano is especially explosive, and while the Methow Valley is expected to get the worst of it, tephra from a previous major eruption left thick deposits in Montana.

Distance to Seattle: 105 miles

Last eruption: 950

Danger level: High

While not as explosive as other nearby volcanoes, Mount Adams could produce lava flows—which the USGS considers a comparatively low risk, since a human can outrun a lava flow. The flows from Mount Adams “typically travel less than [12 miles] from vents,” notes the USGS, “but in rare cases during Mount Adams history more voluminous flows reached lengths of [15 to 30 miles].” Lahars could affect the White Salmon River valley and the Klickitat River canyon.

Mt St Helens, Washington 98616

Distance to Seattle: 185 miles

Last eruption: Last major eruption on May 18, 1980

Danger level: Very high

“Prior to 1980, Mount St. Helens had the shape of a conical, youthful volcano sometimes referred to as the Mount Fuji of America,” notes the USGS. While the 1980 incident, which lasted through 1986, makes up the major eruption that people alive today in the Northwest can remember, it’s had a couple of minor eruptions since then, including a minor eruptive period between 2004 and 2008.

In 1980, volcanic ash reached far enough to the east to cause complete darkness 250 miles to the east in Spokane and a major lahar flowed down into the Cowlitz River, reaching its peak size about 50 miles downstream from the volcano. Lahars destroyed more than 200 homes and more than 185 miles worth of road. There’s one town in the immediate blast zone of the volcano—Cougar—that could experience the more immediate effects like rock fall. Lahar risk stretches down the Toutle and Cowlitz rivers.

The USGS considers Mount St. Helens to be the third highest-risk volcano in the country.

Mount Rainier, Washington 98304

Distance to Seattle: 60 miles

Last eruption: Possible minor eruption in 1894; last major eruption 1,000 years ago.

Danger level: Very high

Seattle’s closest active volcano, aka Tahoma, the mountain of “the mountain is out,” is the third-most-dangerous volcano in the country, according to the USGS assessment. could send lahars south down the Cowlitz River; north in the river basins of the Puyallup, White River, and Carbon River; and west down the Nisqually. Risk spreads out to Tacoma, the Muckleshoot and Nisqually reservations, and down to Randle.

Mt Baker, Washington 98244

Distance to Seattle: 130 miles

Last eruption: 1880 or 1843 (last major eruption 6,700 years ago)

Danger level: Very high

Lahars—or volcanic mudflows—from Baker’s last big eruption left deposits in the Nooksack Valley, and little eruptions were witnessed throughout the 1800s. Its ground hazard zones flow out to Ferndale to the northwest and and down into the Skagit Valley to the southwest; the USGS doesn’t consider tephra, or falling ash and rocks, to be a major concern.

Glacier Peak, Washington 98241

Distance to Seattle: 70 miles

Last eruption: 1700

Danger level: Very high

Glacier’s lahar risk zones stretch down the Skagit River and the north fork of the Stillaguamish river, out to Stanwood, La Conner, and as far out as Samish Bay. The USGS notes that this volcano is especially explosive, and while the Methow Valley is expected to get the worst of it, tephra from a previous major eruption left thick deposits in Montana.

Mt Adams, Washington

Distance to Seattle: 105 miles

Last eruption: 950

Danger level: High

While not as explosive as other nearby volcanoes, Mount Adams could produce lava flows—which the USGS considers a comparatively low risk, since a human can outrun a lava flow. The flows from Mount Adams “typically travel less than [12 miles] from vents,” notes the USGS, “but in rare cases during Mount Adams history more voluminous flows reached lengths of [15 to 30 miles].” Lahars could affect the White Salmon River valley and the Klickitat River canyon.