This is Yosemite Valley. It is the most famous of the many dramatic canyons and valleys that were carved out of California's mountains by the force of glaciers during previous ice ages. Small remnants of those glaciers remain on isolated peaks. They are fields of ice that persist from year to year. Winter snows are packed around them and at high elevations they do not melt in the summer. Now global warming and the protracted drought in California are posing a threat to their continued existence. Over the weekend an incident occurred on Mt. Shasta that provided a dramatic demonstration of the process that is underway.
Fractured Mount Shasta glacier triggers flood
A small Mount Shasta community is on flood watch Monday after a chunk of the Konwakiton Glacier, high on the flank of the 14,179-foot volcano, broke off over the weekend and sent high, muddy flows careening down slope toward Highway 89 and into the renowned McCloud River
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The glaciers on Mount Shasta have been put at risk by drought and warm temperatures. Snow acts as a mortar and a buffer to hold rock and glaciers intact. With no snow for months, hot summer temperatures have melted the surface layers of the glaciers. In my climbs this year, I have seen melting and slippage of the Whitney Glacier, Bolam Glacier, Wintun Glacier, Mud Creek Glacier and Konwakiton Glacier.
Over the weekend, a big chunk of ice gave way to the canyon below. Late Saturday night, Mud Creek was flooded with high, muddy flows that swept down the mountain and plundered a network of creeks near a small wilderness subdivision called the Mount Shasta Forest. The mud washed out several back roads with mud and then fed into the McCloud River, which, in turn, feeds into drought-emptied Shasta Lake, only 26 percent full.
This is the mudslide that resulted from the flood.
This is just part of the pattern of what climate change is doing to California and its Mediterranean climate. It only rains in the winter and the amount that falls in any given winter is always pretty variable from year to year. The present extended drought is one of the most severe that can be historically traced. However, even when more abundant rain fall returns, climate change is reducing the amount of that rain that gets stored in the mountains as snow and then adds to the water supply as it melts in the spring and early summer. These warming temperatures will have an impact of the glaciers that give mountains their scenic white caps. This is Mt. Shasta where this piece of glacier broke off.