But how often?
Dangerous volcanic eruptions in the Pacific Northwest are so infrequent that your odds of being caught in one are extremely low. Plus, they give advance warning - no one needed to die in the Mt. St. Helens eruption; the government ignored the hazard maps drawn up by the geologists so the timber companies could keep logging nearby. The area closed to entry was ridiculously small.
What I question is, why did they leave out heat waves? They kill more people than any other weather event. Of course, the Northwest would have looked even better then - extreme heat is rare, and humidity is low when it does get hot.
Perhaps, to be fair, they should have included the risks from the Northwest's gloomy winters. Many people get very depressed when they don't see the sun for a month at a time. Difficult to quantify just how many suicides and accidents are directly caused by this, though.
