Bucking the Trend: Mount St. Helens Grows a Glacier

Steam, gas and ash coming from the lava dome in Mount Saint Helens in 1982. Photo courtesy USGS. — Steam, gas and ash coming from the lava dome in Mount St. Helens in 1982. Photo courtesy USGS.

The eruption of Mount St. Helens forever holds a place in the memories of many people across the nation. On May 18, 1980, Washington’s great mountain received a geological face lift by blowing up all that stood in its way. The volcanic eruption and ensuing landslide took 57 lives, more than 200 homes, and destroyed almost 200 miles of highway road on that spring day.

The Volcano that Made a Glacier

Who would have thought that with the heat of continuing vulcanism that the crater could give birth to a glacier? But it did. Since the eruption, the world’s youngest glacier has been growing in the crater of the active volcano. After the blast in 1980, a thick collection of loosely arranged rocks gathered on the floor of the crater and protected the accumulating snow from both the heat of the lava dome and the melting rays of the sun. Heavy snows, avalanches, and rock falls, allowed the glacier to grow. It gained about 50 feet a year in thickness and 135 feet per year in length, until 2004.

The crater floor in October, 1980, after the eruption but before Crater Glacier was born. Photo courtesy USGS.

Crater Glacier in October, 2000, prior to the 2004-2008 eruptive cycle. Photo courtesy USGS.

From 2004 to 2008, Mt. St. Helens groaned and steamed again with volcanic activity. A new lava dome formed and the glacier lobes were squeezed and compressed between the caldera wall and the new dome. This caused the ice to move more rapidly downhill and was almost split into two separate glaciers. The volcanic activity melted about 10% of the glacier’s mass and changed it from a smooth crevasse-free glacier to a chaotic jumble of ice falls with many crevasses. The cold rock at the edge of the glacier insulated it from flowing lava and prevented the glacier from melting completely, and possibly causing catastrophic mud flows.

Crater Glacier February 2005. It is nearly split at its south end by the new lava domes. Photo thanks to USGS. — Crater Glacier February 2005. It is nearly split at its south end by the new lava domes. Photo courtesy USGS.

Crater Glacier in October 2006. Photo courtesy USGS.

The Little Glacier that Could

Crater Glacier, officially named the the Tulutson Glacier in 2006 (from the local native Cowlitz language word for ice), is currently over one mile long and 650 feet thick. In the mid-2010s, it is getting about 15 feet thicker and 330 feet longer every year. This glacier, nestled in a warm volcano, is also fighting against a larger climate warming trend as it continues to grow. While there are isolated instances of glacial growth across the globe, most ice sheets and glaciers are melting. The paradoxical success story of Crater Glacier and Mt. St. Helens is particularly spectacular.