It was 20 years ago this month that Mount St. Helens in Washington State erupted. Ash and steam had poured out and avalanches of snow and ice had thundered down the mountain's sides for two months, and then on May 18 the volcano - literally - blew its top. The huge blast of rock, ash and hot gases devastated an area about 230 square miles. Fifty-seven people were killed and many others injured. Many buildings were destroyed.
Erupting volcanoes are no small problems. They can trigger tsunamis, flashfloods, earthquakes, rockfalls and mudflows, and can affect areas hundreds of miles away. The Pacific Rim states of Hawaii, Alaska, California, Oregon and Washington are more at risk.
Is your community at risk? Is your community prepared? Click here for emergency information about volcanoes.