DNR briefs Pierce County, Orting officials on Mount Rainier lahar hazards study

DNR Mt. Rainier Lahar Risk Briefing
LEFT to RIGHT: Jody Woodcock, Pierce County Emergency Management Deputy Director; Hunter George, Pierce County Director of Communications; Kevin Phelps, Pierce County Deputy Executive; Pat McCarthy, Pierce County Executive; Keri Rooney, Director of External Affairs-Pierce County Executive’s Office; Mark Bethune, Orting City Administrator; Tim Walsh, DNR Chief Hazards Geologist; and Recip (Ray) Cakir, DNR Hazards Seismologist. Photo: Bob Redling/DNR.

Officials from Pierce County, including County Executive Pat McCarthy, were briefed Tuesday afternoon (July 31) on DNR’s latest estimates of the economic impact of a major lahar (volcanic mudflow) from Mount Rainier. DNR’s Chief Hazards Geologist Tim Walsh explained how the department used mapping and loss-estimation software to compute a potential of $6 billion in structural damages to Puyallup Valley communities from a large lahar.

Also attending the Tuesday afternoon briefing were Orting City Administrator Mark Bethune and Pierce County Deputy Executive Kevin Phelps.

Among the eight major drainages from the volcano, geologists consider the northwest side a likely origination point due to the many weakened rocks there — lahars can be caused by landslides and earthquakes as well as by volcanic eruption. The Puyallup River Valley also is the most populated of the several potential routes for a  major lahar from Mount Rainier.

Because lahar-related flooding has the potential to reach as far as Commencement Bay and Elliott Bay, including the ports of Seattle and Tacoma, community officials are paying close attention to hazard estimiates and plans to mitigate the potential losses to lives and property.

View online maps of likely lahar flows from Mount Rainier, including the locations of properties by street address, on the DNR Geology Portal’s Mount Rainier Lahar (Volcanic Mudflow) Hazards – Property at Risk map. Or download the full report: Loss Estimation Pilot Project for Lahar Hazards from Mount Rainier, Washington, which was funded by the American Recovery and Reinvestment Act.

DNR offers technical assistance, mapping, education and other assistance to citizens and government officials and planners on a range of subjects, including geologic hazards.

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