March 31, 2014

UW experts part of technical team investigating Snohomish County mudslide

News and Information

A national team co-led by a University of Washington geotechnical engineer will investigate what caused the March 22 mudslide in Snohomish County and what effects the disaster had on the nearby residential communities.

An aerial view of the Snohomish County mudslide.

Weldon Wilson, Washington State Patrol

An aerial view of the Snohomish County mudslide.

The Geotechnical Extreme Events Reconnaissance Association is mobilizing to collect information about the landslide that occurred on a steep slope above the North Fork of the Stillaguamish River near Oso, Wash., more than a week ago, killing more than 20 people with 30 still missing.

The group will try to understand why the slope collapsed in the hope that a similar disaster can be prevented, said Joseph Wartman, a UW associate professor of civil and environmental engineering who is leading the investigation with Jeffrey Keaton, principal engineering geologist at AMEC Americas.

Read the Geotechnical Extreme Events Reconnaissance Association’s news release

“The purpose is to collect data before the site is changed or altered in rescue and recovery. There is a lot of valuable information about how that landslide occurred in the landscape itself,” Wartman said. “Ultimately, we want to learn from these disasters so we can prevent reoccurrence of future catastrophes.”

Local team members, including Wartman and UW geomorphologist David Montgomery, are hoping to visit the landslide site this week, followed by a visit next week from the entire reconnaissance team of six experts from universities, government agencies and industry.

The Geotechnical Extreme Events Reconnaissance Association is a National Science Foundation-funded group of experts that responds quickly when a geologic disaster happens. The association tries to collect technical data within days of a disaster to inform future long-term investigations. Some of its disaster investigations include the Colorado floods in 2013, Hurricane Sandy in 2012 and recent catastrophic earthquakes in Chile, Haiti, Japan and New Zealand.

The investigators aim to piece together what happened in the Western Washington disaster by collecting field measurements and gathering details from people who witnessed the landslide. It’s not intended to be a long-term investigation, but rather a quick-turnaround initiative that could help guide future investigations, Wartman said.

The team plans to document the mudslide by taking photos, talking with witnesses, measuring parts of the landslide and looking at satellite imagery from various points on the landscape.

Data collection will be quick, and the team plans to post its observations and findings within a month on the association’s website. The group appears to be the only one currently collecting technical data on the mudslide, though other experts have been involved in making sure the area is safe for rescuers.

The team will not be involved with rescue and recovery work and hopes to strike a balance between not interfering in those efforts while making sure to document the disaster before evidence is lost, Wartman said.

“We will be collecting perishable, important technical data that will soon disappear,” he said. “We hope to directly observe and record the effects of this landslide on the community. As a nation, we don’t have a lot of information about the human and capital losses of a landslide disaster.”

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For more information, contact Wartman at wartman@uw.edu or 206-685-4806.

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