The USGS just released its latest volcanic threat assessment report (amateur volcanologists may read here)—a pretty interesting read, actually—which describes the threat level of the 160 active volcanoes in the US. Roughly 20 percent of those active volcanoes are in national parks or national monuments, and each active volcano area gets a matter-of-fact rating: very low, low, moderate, high, and very high. These are of course relative to the frequency of volcanic eruptions over geologic time scales. Just because a volcano is listed as a “very high” threat does not mean it’s on the verge of a full-scale eruption at any moment. According to the USGS, anyway.

Volcanic eruptions are not typically a thing most outdoor enthusiasts probably spend much time considering when choosing a national park to visit, but there are a handful of popular parks that hold volcanoes that the USGS is keeping an eye on. Unsurprisingly, Hawai’i Volcanoes National Park well-known for its very active Kīlauea volcano which erupted this summer, topped the list, with Kīlauea as the most threatening active volcano being monitored (very high threat), with Mauna Loa, also in the park, listed at #16 (very high threat).

Number two is Mt. Rainier National Park with Rainier also considered a very high threat.

The full list of parks and monuments and their volcanoes with high or very high volcanic threat levels is below. Pretty cool, actually, to be waltzing around above so much unstable geologic and volcanic activity just below the surface. Unless you’re there when it blows, of course.

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Hawai’i Volcanoes National Park: Kīlauea (No. 1 overall, very high threat) and Mauna Loa (No. 16, very high threat).

Mount Rainier National Park: Mt. Rainier (No. 2, very high threat).

Lake Clark National Park and Preserve: Illiamna Volcano (No. 20, high threat) and Redoubt Volcano (No. 4, very high threat).

Lassen Volcanic National Park: Lassen Peak (No. 11 overall, very high threat)

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Crater Lake National Park: Crater Lake  (No. 17 overall, very high threat).

Yellowstone National Park: Yellowstone caldera (No. 21, high threat)

Aniakchak National Monument: Aniakchak Crater (No. 22, high threat).

Katmai National Park and Preserve: Mount Martin (No. 25, high threat), Mount Mageik (No. 26, high threat), Trident Volcano (No. 27, high threat), Novarupta (No. 37, high threat), Mount Griggs (No. 42, high threat), Mount Katmai (No. 28, high threat), Snowy Mountain (No. 52, high threat), Mount Denison (No. 87, moderate threat), Mount Steller (No. 88, moderate threat), Kukak Volcano (No. 66, moderate threat), Kaguyak Crater (No. 43, high threat), Fourpeaked Mountain (No. 53, high threat), and Mount Douglas (No. 54, high threat).

Wrangell-St. Elias National Park and Preserve: Mount Wrangell (No. 101, moderate threat) and Mount Churchill (No. 38, high threat).

Lava Beds National Monument: Medicine Lake (No. 45, high threat)