When Mt. Rainier Blows, What Will Be Left?

Joshua McNichols of KUOW.org spoke with a local geologist and emergency management employee to find out what residents of northwest Washington state could expect when Mount Rainier finally erupts. Geologist Carolyn Driedger anticipates that beyond the lava and giant boulders launched into the air, the real calamity will result from the melted snow which would create flash flooding down the mountain. The resulting mudflows, or lahar, would do massive damage to the surrounding environment.

No one knows how big a lahar would be for Mount Rainier – or how far it would travel. But [Scott Heinze, with the Pierce County department of emergency management] wants to show me how far it could come. He takes me to Fireman’s Park, high on a bluff above the port of Tacoma. “You can see the cranes over there,” he says. “You can see the rail yard, you can see 167 and I-5, a steady stream of semis that are coming in and out of port.” Everything we see, he told me, could be drowned by a lahar. Routes connecting Tacoma to Seattle could be buried. Tacoma could face shortages of food and supplies. Many of its hydroelectric dams and water sources also lie in lahar zones.

Heinze advises people to get off the valley floor quickly and to have an evacuation route planned out ahead of time. He anticipates that the chaos from the evacuation will lead to more fatalities.