Washington’s most overlooked mountaintop

May is Volcano Awareness Month in Washington State, and DNR’s Ear to the Ground is featuring one of our state’s five active volcanoes throughout the month.

Today, let’s take a look at Washington’s least-recognized volcano, Glacier Peak.

ger_popular_north_cascades_glacier_peak_aerial.pngLocated in a wilderness area in eastern Snohomish County, Glacier Peak is not easily visible from any major metropolitan centers, and so the hazards (and attractions) of this 10,451-foot peak may get overlooked. The peak wasn’t known by settlers to be a volcano until the 1850’s, when Native Americans mentioned to naturalist George Gibbs that “another smaller peak to the north of Mount Rainier once smoked.”

Glacier Peak has produced larger and more explosive eruptions than any other Washington volcano except Mount St. Helens. Glacier Peak is only 70 miles from Seattle, which puts it closer to the state’s largest metropolitan area than any volcano except Mount Rainier.

ger_hazards_volc_usgs_glacierpeak_laharEruptions of Glacier Peak have characteristically produced large volumes of volcanic ash and airborne pumice that could endanger the closest centers of population. The last major eruption of Glacier Peak was around the year 1700.

Geologic mapping has documented the extent of previous lahar runout in the Skagit and Stillaguamish River valleys. While Glacier Peak has shown no sign of eruption in the last few decades, the lahars deposits in the river valleys from past eruptions are a reminder of the hazard Glacier Peak poses to the communities living in the valleys adjacent to the volcano.

Glacier Peak
Glacier Peak viewed from the east. Photo: USGS.

We want our awareness-raising about Washington State volcano threats to encourage preparation and not raise unnecessary alarm, so here is the very latest on alert levels for Cascade Range volcanoes from the U.S. Geological Survey Cascades Volcano Observatory.

Housed in DNR, the Washington Geological Survey maps, monitor and educate the public, governments and others about geologic hazards, including volcanoes.

Our geologists have mapped lahar deposits from Glacier Peak in the Skagit River Valley and helped produce hazard maps so those living in the shadow of Glacier Peak can know what to expect if – and when – our shy volcanic neighbor produces lahars.