A volcano is an opening in the earth's crust that allows lava (molten rock), gases, and debris to escape to the surface. Most volcanos are dormant (inactive) and pose no immediate risk. Others, however, are active and can cause catastrophic damage if they erupt.
While Alaska, Hawaii, California, and Oregon have the most active volcanoes in the U.S., other states and territories have them too. If you live in or plan to visit an area with volcanic activity, you should understand and prepare for the risks of a volcanic eruption.
Note: Volcanic eruptions can be life-threatening. Always follow the guidance of local authorities if you receive a volcanic eruption warning.