The United States is one of the world's most volcanic countries having over 10% of the world's potentially active volcanoes. The U.S. Geological Survey released a list of the most dangerous volcanoes in the U.S. in 2018. According to this list, Mount Kīlauea in Hawaii, and Mount St. Helens and Mount Rainier of Washington rank in the top 3 positions. The rankings were created based on threat assessment of the country's volcanoes by measuring their potential for eruption and severity of human impacts. The rankings offer to provide vital information that can be used by the USGS and other organizations to understand which volcanoes deserve greater monitoring and research. It will allow them to effectively help local communities to prepare for future eruptions if any.
According to the list created by the USGS, 18 volcanoes have been included in the “very high threat” category. 10 of these most dangerous volcanoes have been mentioned below.
Kīlauea is one of the most dangerous volcanoes in the US. It is an active shield volcano that together with four others form the island of Hawaiʻi. The volcano emerged above the sea level about 100,000 years ago along the island's southeastern shore. Kīlauea has remained continuously active from 1983 to 2018. Its activity destroyed the town of Kalapana in 1990. In 2018, two other places, Kapoho and Vacationland Hawaii, became victims of this volcano's wrath. Timely monitoring of the volcanic activity helped prevent the loss of lives in the area. However, bigger eruptions in the future could prove fatal.
9. Mount St. Helens
This active stratovolcano is located in Skamania County, Washington. It is part of the Cascade Volcanic Arc in the Pacific Ring of Fire. Pyroclastic flows and ash explosions from the volcano pose a serious threat to the nearby settlements and wild habitats. Mount St. Helens is held responsible for the deadliest event in the country's recent volcanic history. On May 18, 1980, the volcano erupted killing 57 people and destroyed homes, bridges, railways, and highways. A debris avalanche resulting from the eruption was the main killer. Later, the Mount St. Helens National Volcanic Monument was set up in the area to preserve the volcano and study it in detail to prevent such future mishaps.
8. Mount Rainier
Another volcano in Washington also finds its place on the list of the country's most dangerous volcanoes. Mount Rainier, also known as Tahoma, is an active stratovolcano. It is located in the Mount Rainier National Park near the city of Seattle. It is the highest mountain in Washington and has an elevation of 4,392 m. As the mountain has a large amount of glacial ice, a major eruption of the volcano can potentially trigger massive lahars that can drown the entire Puyallup River valley below. Thus, the lives of about 80,000 people are at risk in the zone surrounding this volcano.
7. Redoubt Volcano
Redoubt Volcano is an active stratovolcano located in the Lake Clark National Park and Preserve in Alaska. It is 3,108 m tall making it the highest peak in the Aleutian Range. The mountain was first recorded in 1778 by Captain James Cook. Since then, four major eruptions have been accounted for: in 1902, 1966, 1989 and 2009. The 1989 eruption spewed volcanic ash as high as 14,000 m that even caught an airplane in its plume. Luckily, the flight managed to land safely at Anchorage. Since the eruption was predicted, lives were not lost. However, a USD 160 million worth of damage to property occurred during the disaster.
6. Mount Shasta
The southern end of California's Cascade Range hosts a potentially deadly volcano called Mount Shasta. With an elevation of 4321.8 m, it is the second-tallest peak in the Cascades. The Shasta–Trinity National Forest includes the mountain and its surrounding area. Mount Shasta has erupted an average of every 800 years during the last 10,000 years. However, the eruption frequency of the volcano has increased recently. Although the volcano has been geophysically quiet for the past 15 years, it might have a major eruption anytime in the future. Since ice covers the slopes of Mount Shasta, any large eruption might be accompanied by lahars that can cause significant damage to lives and property.
5. Mount Hood
This potentially active stratovolcano is located in the Cascade Volcanic Arc in Oregon. It is considered to be the most dangerous volcano in the state. It is estimated that there is a 3 to 7% chance that the volcano will erupt in the next 30 years.
4. Three Sisters
The Three Sisters refer to three peaks that are the 3rd, 4th, and 5th highest peaks in Oregon. They are located close to each other in the Cascade Volcanic Arc. All of them are over 3,000 m tall and are part of the Three Sisters Wilderness. The Three Sisters are named North Sister, Middle Sister, and South Sister. While it is unlikely that the first two will erupt again, the South Sister is regarded as potentially active. It last erupted about 2,000 years ago.
3. Akutan Island
This stratovolcano is America's eighth most dangerous volcano. It is located in the Aleutian Islands of Alaska where it attains an elevation of 1,303 m above sea level. A major explosion 1,600 years back led to the formation of a 2 km wide caldera on this volcano. The volcano is currently active and has erupted several times in the past. In 1978, lava from the volcano reached within 2 km of the coast. The most recent eruption of Mount Akutan happened in 1992. Fumarolic activity and hot springs in the area remind one of the potentially lethal nature of the volcano.
2. Makushin Volcano
Another volcano from Alaska finds its position in the list of the 10 most dangerous volcanoes in the US. The Makushin Volcano is an ice-capped stratovolcano located on the Unalaska Island of the Aleutian Islands archipelago. It is 2,036 m tall. It has erupted at least two dozen times in the past thousands of years. The most recent eruption of this volcano occurred in 1995.
1. Mount Spurr
Also located in the Aleutian Arc, Mount Spurr has an elevation of 3,374 m. It is a large lava dome with a caldera at its summit. An increasing number of earthquakes in 2004 in the area around Mount Spurr led to new concerns about its activity as earthquakes in a volcanic region often indicates movement of magma underneath the volcano. Some volcanic activity in the form of debris flow was noted in the area in 2005. Thus, Mount Spurr is regarded as one of the most dangerous volcanoes in the country.