The volcanic Mt Rainier is grumbling. But it’s not what you think. At least not yet.

According to reports from the Seattle Times, the glaciers atop Rainier have melted to the point where they are becoming unstable. Particularly so with Tahoma Glacier which, all throughout July to mid August, has emitted large floods of muddy, ice-choked water. Tahoma sent its floods rumbling down the mountainsides, filling streams and rivers with roiling, brown outflows.

These glacier outburst floods issuing from Rainier have packed quite a punch. They’ve been strong enough to shake the earth, setting off seismographs in the region of Rainier. It’s a shaking and quaking that’s tumbled boulders down the mountainside, gouged out new flood channels and smashed great swaths of trees.

(Over recent months, the Tahoma Glacier on the southwestern face of Mt. Rainier has been issuing large flows of glacial outburst material. Those familiar with the mountain believe that a warming climate may have pushed Rainier’s glaciers into a new era of destabilization. Image source: Glaciers of Washington.)

Zachary Jones noted in his eyewitness report to the Seattle Times:

“The rumble was getting louder and trees were falling down and it looked like a big pile of rubble was raging down the dry creek bed. We saw huge boulders, half the size of a Volkswagen bug, just raging down and falling over each other (see related video here).”

Scientific Link Between Glacial Melt, Increase in Volcanic Activity

Back during the 1980s and 1990s, Rainier went through a similar period of warming-stoked glacial destabilization. Now, the heat is even worse. A new phase of glacial retreat has isolated Tahoma and set it on path toward more rapid melt. It may mean that coming years and decades host a ramping of glacier outbursts for Rainier. It may also mean a changing of the weight loading atop Rainier’s volcanic vents and magma chambers. Setting up a rising risk for increased volcanic activity from Rainier as its overburden rocks and underlying magma structures develop a new equilibrium.

Recent, though rather controversial, science has established a link between glacial retreat over and near volcanic systems and increased volcanic activity. In particular, studies focusing in on Iceland have linked periods of glacial melt with increased periods of volcanism. Though it is uncertain whether Rainier will succumb to the added stresses of glacial melt and respond by entering a new period of volcanic awakening, the melt human warming is setting off does provide a new stress to one of the most dangerous volcanic systems in the western US.

In other words, Rainier’s grumbling glaciers are bad enough without adding in a volcanic bassline.

Links:

Rainier Melting Unleashes Glacial Outbursts

Climate Change’s ‘Waking Giant’

How Will Melting Affect Volcanic Hazards in the 21st Century?

Hat Tip to Andy in San Diego