Mount Shasta’s Glaciers are Shrinking
A recent blog post From a Glacier’s Perspective on the American Geophysical Union Blogosphere website detailed the continued shrinking of Mount Shasta’s glaciers. This news comes almost 15 years after a study by University of Santa Cruz reported that the glaciers were growing. The “growing glaciers” study is frequently relied on by members of the public to insinuate that those of us around Mount Shasta will have no shortage of water in the future. The current condition of the glaciers on Mount Shasta is perilous. The largest glacier on the mountain, Whitney Glacier has seen its upper and lower sections completely disconnect and the mass of the glacier reduced by 15-20% this summer alone.
We have seen several events that come as a result of glacial ice loss this summer.
On the south side of the mountain in McCloud, a debris flow has inundated Mud Creek and forced the muddy flow out of its channel where it has taken out a Forest Service road and limited access into the Mount Shasta Forest subdivision east of McCloud. The events in Mud Creek come in pulses and it is suspected that small lakes of runoff collect at the base of Konwakiton and Mud Creek Glaciers and then the water crests the dams and forms debris flows. The glaciers on the south side of Mount Shasta are quite small relative to the north-side glaciers. Absent sufficient winter snowpack to insulate the ice, these glaciers have been declining in size for a long time and were never included in the Santa Cruz study.
On the north side of the mountain, Whitney Creek swelled with mud, boulders, and the recent Lava fires debris after an intense thunderstorm which caused rain up to 14,000 feet on the mountain. Whitney Creek is part of Shasta River watershed and its cold intermittent summer flows are one of the reasons the Shasta is a historic salmon producer. This summer’s debris flow threatened highway 97, but the activity has since diminished to normal levels. Whitney has retreated and had its upper and lower sections separate this summer.
Mount Shasta is part of a hydrologic system where many of her surrounding rivers and streams emanate from large springs at the foot of the mountain. Spring fed river systems differ from snow melt run-off river systems. Spring fed rivers are usually colder water and the timing of their runoff can happen later in the summer than a strictly snow melt run-off river. Spring output around the mountain has been very low this summer because of the drought. Many historic springs have seen flow levels greatly reduced or complete cease.