The United States has approximately 161 active volcanoes. Of these, 55 of them pose serious threats because of where they are located, how they formed, their ability to cause a great deal of damage to infrastructure, and the threat they pose to property and people. However, most volcanoes in the United States are located on or near federal land, which, fortunately, are not heavily populated areas.
Over the last 25 years, there have been 47 eruptions and around 16 significant events related to volcanoes, according to the United States Geological Survey (USGS). The USGS operates the USGS Volcano Hazards Program, providing around the clock monitoring that helps give notice of a potential event as early as possible. However, only a handful of volcanoes are monitored with the most current systems and instruments. In fact, 40% of the most serious threats are only monitored for significant changes in activity, which would be helpful in trying to model or predict their future behavior.
Some of the most active volcanoes in the United States are in Alaska, California, Hawaii, Oregon, Washington, Wyoming, and the North Mariana Islands.
Those where the threat score is higher are Alaska's Redoubt, Mount Okmok, Akutan Island and Mount Spurr. Threat scores also rose for Oregon's Newberry Volcano and Wyoming's Yellowstone.
Steps you can take to prepare for a volcanic eruption:
- Get to know your community's emergency management plans and warnings.
- Be aware of the hazards that could accompany volcanic activity- floods, landslides, mud-flows, rock falls, earthquakes, falling ash, acidic rain, and tsunamis.
- Have an evacuation plan and supplies ready.
- Have your family’s emergency communications plan in place, and make sure everyone understands it.
- Have disaster readiness kits assembled and ready to go.
- If an evacuation order is given, take heed and move to a safer area.
- Avoid going downstream or downwind if at all possible.
- Listen to your hand-crank or battery-powered NOAA Weather Radio.
- If you are caught indoors, close and seal all doors, windows, and dampers.
- Move pets and livestock into enclosed buildings.
- If you are caught outdoors, seek shelter inside, and wear long-sleeved shirts, pants, goggles, and dust cover masks.
- Do not drive during heavy ash fall.
- Try to help your neighbors if it is safe to.
When a volcano erupts, hot lava and gasses are discharged into the air. The worst kind of lava is often referred to as a “glowing avalanche.” With temperatures that exceed 1200 degrees Fahrenheit, this flow can reach speeds of 120 MPH and range 10 to 15 miles from the source. Eruptions can have long-term consequences that include large populations being forced to move. They cause temporary food and water shortages as well as ash that can damage respiratory systems.