Over 45,000 WA students participate in lahar evacuation drill

Over 45K Washington students participate in world’s largest lahar evacuation drill

Tens of thousands of Pierce County students participated in a drill aimed at preventing disaster if a debris flow happened near Mount Rainier.

PIERCE COUNTY, Wash. - In May 1980, Mount St. Helens erupted, forever changing how volcanoes were monitored and how the community prepares for future eruptions.

That eruption is why the month of May is now considered "Volcano Awareness Month," and recently, the world’s largest lahar evacuation drill was held here in Washington.

Just west of Mount Rainier, more than 45,000 students from schools across Pierce County participated in the drill.

"Those areas could potentially be impacted by a large-scale lahar that could come from Mt. Rainier, so those communities practice evacuating their school districts in case a lahar was going to come into the valley," said Holly Weiss-Racine, Geologist and Outreach Coordinator for the U.S. Geological Survey (USGS) Cascades Volcano Observatory.

Weiss-Racine tells FOX 13 lahars or mudflows are common when it comes to the type of volcanos we have here in the Pacific Northwest.

"As they’re moving, they’re more like a slurry of wet concrete as they come down the river valleys," Weiss-Racine said. "Based on modeling, we would have about 60 minutes in a worst-case scenario of a very large, fast moving lahar to get people out of areas like Orting."

These evacuation drills are held every other year. On March 21, students ages 5-to-18 from five different school districts participated in the drill, including Puyallup, Sumner-Bonney Lake, Orting, White River, and Carbonado.

"Watching the students participate and know that it is physically possible to get them out of the inundation zone in the time that we would have if a lahar occurred really helped me feel better about the idea of being able to evacuate those communities," Weiss-Racine said.

She adds, USGS knows of at least 11 lahars from Mount Rainier in the last 6,000 years, with the most recent being 500 years ago.

"We live in a very tectonically active part of the country; we talk about ‘the big one’ in reference to a large subduction zone earthquake, and then we have these beautiful volcanoes that punctuate our landscape and knowing what the geologic hazards are in your area is really important to your preparation," Weiss-Racine said.

FOX 13 asked what the next largest lahar evacuation drill was in comparison to the Washington drill with 45,000 participants, and Weiss-Racine said there were some in Japan that had a few thousand participants.