Did you know Mount Rainier is an active volcano? While we can't say how many times Rainier has erupted over the course of its existence, we do expect it to erupt again someday. The only questions is matter of when, and to what degree.
, "Lahars look and behave like flowing concrete, and they destroy or bury most man-made structures in their paths."
Should Mount Rainier erupt, everyone in the valley will need to avoid the oncoming lahar by evacuating to higher ground. It's for this reason that the lahar warning siren system is tested on the first Monday of each month, and it's also why we provide a map showing recommended Volcano Evacuation Routes.
Learn more about Mount Rainier and lahars, courtesy of the USGS.
Bridge destroyed by lahar in North Fork Toutle River during eruption of Mount St. Helens, May 18, 1980.
(Credit: Waitt, Richard. Public domain.)
Lahar Warning System
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New Program Connects Girl Scouts to Volcanic Neighbors
Just in time for the 41st anniversary of the 1980 eruption of Mount St. Helens, Girl Scouts of Oregon and Southwest Washington (GSOSW) announced today a brand new program, Our Volcano Neighbors, developed in partnership with the Mount St. Helens Institute (MSHI) and the United States Geological Survey (USGS). The program aims to teach girls about the cultural and geographical significance of Mount St. Helens and other volcanoes through hands-on STEM activities, career exploration and outdoor adventures.
- Lahar Detection and Volcano Monitoring - National Park Service (NPS)
- Lahars on Mount Rainier - USGS
- Mount Rainier Hazards - USGS
- Volcanoes and Lahars - Department of Natural Resources (DNR)
- Automated Lahar Detection Systems - USGS
- Are You Ready for An Eruption?
- Volcanic Hazards in Washington State
- Evacuation and Preparation
- Are You Volcano Ready?
- Pacific Northwest Seismic Network (PNSN)
- What did the previous test siren sound like?
- How Mount St, Helens Changed Our World