Earthquake or volcano -- worst case natural disaster?

Jan 7, 2011

With massive flooding in Australia in the news, or earthquakes in South America, perhaps it’s no surprise that 2010 was the most deadly year in a generation for natural disasters around the globe.  What’s the worst we might face here in western Washington?

Listen by clicking the audio 'play' arrow above

The obvious big one would be a massive earthquake off the Washington coast, on the Cascadia subduction zone, knocking down buildings across the region and spawning a tsunami. 

Ted Buehner of the National Weather Service calls that the most devastating disaster we could face, especially if it comes during a rain-soaked winter.

The second-place Armageddon scenario?  A volcanic eruption of Mt. Rainier, also during winter, when there’s already rain and wind storms, making it hard to send aid and fix power lines.  

"We have volcanoes that are formed by heat, that are now covered by vast amounts of ice and snow," says Carolyn Driedger of the Cascades Volcano Observatory (part of the U.S. Geological Survey). 

That "snow-clad beauty" is also why it's a hazard, she says, because of the floods an eruption would spawn. As much snow and ice sits on top of Mt. Rainier as on Mt. Baker, Mt. Hood and all the other Cascade volcanoes combined.  It’s ironic to have ice on a hot-pot, and dangerous when it melts.

Driedger says if even a relatively small amount of ice on top of Mt. Rainier were to melt, it would trigger mudslides that could cover whole towns.  Most of those towns are aware of the danger, and some. such as Orting, even have annual evacuation drills. 

Scientists are doing their part to prepare, with monitors placed on all 13 Cascade volcanoes (although the single monitor on remote Glacier Peak is a bit unreliable). 

Typically, there’s about a one-week advance warning before eruptions, through small earthquakes and bulges on the surface.