Alpine Glaciers / Volcanos

Glacier Peak:

Glacier Peak is one of the most active of Washington’s volcanoes. It is a stratovolcano and is 10,541 feet tall. (USGS). Glacier Peak is a small stratovolcano. Its relatively high summit is a consequence of its location atop a high ridge, but its volcanic portion extends only 1,600–3,200 feet above this ridge.

The peak wasn’t known by settlers to be a volcano until the 1850’s, when Native Americans mentioned to naturalist George Gibbs that ” (volcano.si) another smaller peak to the north of Mount Rainier once smoked.”  Glacier Peak is not prominently visible from any major population center, and so its attractions, as well as its hazards, tend to be overlooked. Glacier Peak as well as Mt. Saint Helens are the only volcanos in Washington State to have erupted in the past 15,000 years. A little more than 13,000 years ago, a sequence of nine tephra eruptions occurred within a period of less than a few hundred years. Associated with these eruptions were pyroclastic flows. Mixed with snow, ice and water, these formed lahars that raced into three nearby rivers, filling their valleys with deep deposits.

Mount Baker:

Mount Baker happens to be the highest peak in all of the North Cascades at 10,781 feet and is formed of mostly andesite lava flows. (USGS) This active volcano formed during the Pleistocene epoch approximately 1 million years ago during the last glacial period. The most recent major eruption at Mount Baker, about 6,700 years ago, was accompanied by a major flank-collapse event that caused lahars to rush down the Nooksack River and then eastward into Baker Lake. In 1975-76, Sherman Crater, immediately south of the summit, exhibited signs of renewed volcanic activity as a result of magma intruding into the volcano but not erupting.