The 20 most dangerous volcanoes in the US, ranked

The federal government's ranking of which volcanoes pose the most threat to the US has been more updated for the first time since 2005.

Each one gets two scores: an overall threat score and an aviation threat score.

The overall threat score looks at 24 factors including how often it erupts, how powerful its eruptions are, the nearby population size, and how many people have been killed or evacuated before.

The aviation threat score is similar but focuses on factors like how close a volcano is to airports, and which flight paths go nearby.

Here are the 20 volcanoes that post the biggest risk:

19: Iliamna Volcano, Alaska. Threat Score: 115. Aviation Threat: 34.

Avalanches are common on the volcano.

19: Mount Okmok, Alaska. Threat Score: 117. Aviation Threat: 47.

The USGS calls Mount Okmok "

18: Long Valley Caldera, California. Threat Score: 129. Aviation Threat: 29.

17: Crater Lake, Oregon. Threat Score: 129. Aviation Threat: 37.

magma

16: Mauna Loa, Hawaii. Threat Score: 131. Aviation Threat: 4.

lava

15: Glacier Peak, Washington. Threat Score: 135. Aviation Threat: 37.

explosive eruptions

14: Mount Baker, Washington. Threat Score: 139. Aviation Threat: 15.

13: Newberry Volcano, Oregon. Threat Score: 146. Aviation Threat: 30.

12: Augustine Volcano, Alaska. Threat Score: 151. Aviation Threat: 48.

Its 2006 eruption saw blasts in Alaska for over 20 days and

11: Lassen volcanic center, California. Threat Score: 153. Aviation Threat: 32.

More than 190,000 Californians live in a volcano hazard zone, according to the Los Angeles Times.

10: Mount Spurr, Alaska. Threat Score: 160. Aviation Threat: 48.

9: Makushin Volcano, Alaska. Threat Score: 161. Aviation Threat: 47.

Makushin last erupted in

8: Akutan Island, Alaska. Threat Score: 161. Aviation Threat: 47.

Akutan is "

7: Three Sisters, Oregon. Threat Score: 165. Aviation Threat: 30.

Three Sisters hasn't erupted in 2,000 years, but it

6: Mount Hood, Oregon. Threat Score: 178. Aviation Threat: 30.

Mount Hood is close to "

5: Mount Shasta, California. Threat Score: 178. Aviation Threat: 39.

Nearby towns, like Mount Shasta and Weed, are close enough to the volcano that they could be at risk in an eruption.

4: Redoubt volcano, Alaska. Threat Score: 201. Aviation Threat: 48.

3: Mount Rainer, Washington. Threat Score: 203. Aviation Threat: 37.

2: Mount St. Helens, Washington. Threat Score: 235. Aviation Threat: 59.

1: Kilauea volcano, Hawaii. Threat Score: 263. Aviation Threat: 48.

This active volcano is continuously erupting and was given the highest threat score by the US Geological Survey.

The 20 most dangerous volcanoes in the US, ranked

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