The volcano is responsible for the deadliest eruption in the U.S., yet many mysteries remain about the closely watched peak, including why it formed in the first place.
40 Years After the Mount St. Helens Eruption
Why does the volcano's location continue to mystify geologists? Did you know its fiery breath carved breathtaking ice caves into the land? Four decades after Mount St. Helens roared to life in the deadliest eruption in U.S. history, we take another look at one of the country's most prominent—and infamous—peaks.