The devastation wrought by Hurricane Katrina has revived scenarios of other disasters past and future, including the eruption of Mount St. Helens and Mount Rainier.

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Seattle and Tacoma live under the double threat of earthquakes and active volcanoes. Two of the country's three most dangerous volcanoes, according to the U.S. Geological Survey, are in Washington: Mount Rainier and Mount St. Helens. The latter erupted about 20 years ago, covering the Portland, Ore., metropolitan area in a blanket of ash. An eruption of Mount Rainier, scientists believe, could send a deadly mudflow down its slopes and could kill thousands.

"A lot of people probably question us, 'Why do you spend so much time preparing for an event that might never happen?' " said Jody Woodcock with the Pierce County Department of Emergency Management. "My response is, 'But it could happen."'

Like the New Orleans flooding, an eruption of Mount Rainier, Woodcock said, "is something we really can't comprehend."

The last time such a mudflow -- made of melted ice, dirt, rocks and debris, and called a lahar -- came down Rainier was 500 years ago. It could happen again at any time, though residents would presumably have several days warning, as volcanic activity can be monitored.

If the mudflow was big enough it could reach Tacoma, but probably not Seattle, where the biggest threat is an earthquake. A strong quake shook Seattle in 2001.

After Katrina, local businesses and volunteers showed an increased awareness of disaster planning and response -- flooding local agencies with offers to house evacuees and help in the relief effort. Woodcock and others hope they can tap into these newly discovered resources should a disaster befall the Puget Sound region. To be sure, they will be watching what goes on in Louisiana and Mississippi.

"I think we'll learn a lot from watching the recovery process," Woodcock said, "seeing communities completely rebuild. I think emergency managers from around the world are going to be watching."