The Mount Lyell Glacier No Longer Moves

Photo of me taken by Sacha Heath in 2003, back when
the Lyell Glacier (behind me) was still active, as it has
been for about the last 400 years.

I just got the news from Margaret Eissler. Greg Stock, the Yosemite National Park Geologist, has pronounced the Mount Lyell Glacier inactive. The largest glacier in Yosemite National Park no longer moves downhill, as active glaciers do.

This is very sad news. It is like Negit Island no longer being an island, or the Casa Diablo Geyser going inactive, or Tulare Lake no longer being a lake, or the Colorado River no longer flowing through its delta to the sea, or Walker Lake Nevada's Lahontan Cutthroat Trout fishery being decimated, or Lake Tahoe losing its clarity, or the loss of the starry sky due to light pollution, or the loss of silence due to noise pollution. It is a huge geographical, geological, historical, and cultural event.

The Mount Lyell Glacier no longer moves. Because of us. We just killed the Lyell Glacier.

It is sad because it has been caused by humankind, and was preventable, just like all these other tragedies. It is also a glacier that spared my life and taught me some things, so I feel a personal connection to it.

But we can console our sadness with the thought that the Lyell Glacier isn't dead, it is just inactive. Just like the Mono Craters are still volcanoes, the Lyell Glacier is still a glacier. Glaciers and volcanoes are processes that will recur. The Lyell Glacier has only been active since the Little Ice Age. When the climate turns cold again, it will recur, just as surely as the Mono Craters will erupt again. Both leave marks upon the landscape, and then go dormant for a few hundred years before they come back. John Muir himself said:

Every glacier of the Sierra fluctuated in width and depth and length, and consequently in degree of individuality, down to the latest glacial days.
(The Yosemite, Chapter 11)

The loss of the Lyell Glacier is a cultural and historical event because it was not only the largest glacier in Yosemite, but it was part of the massive Tuolumne Glacier that carved Hetch Hetchy Valley and Tenaya Canyon. His observations of the "remnants" of the Tuolumne Icefield, including the Lyell Glacier, helped John Muir prove Josiah Whitney wrong. Whitney believed there were no glaciers in the Sierra, and that Yosemite Valley was created by a great cataclysmic earthquake. John Muir believed it was created by a glacier, and he found them and measured their movements in the headwaters of the Tuolumne River and Merced River. John Muir put stakes in the McClure Glacier (which is next to the Lyell Glacier and remains active for now) and observed them move downhill up to an inch per day. He proved that glaciers lived in the Sierra.

In today's climate, now there is one less, and we will continue losing them. When there are no more glaciers in the Sierra, Whitney will be right about there being no living glaciers in the Sierra, and John Muir wrong.

Adding insult to injury, humankind's actions not only caused the loss of John Muir's beloved Hetch Hetchy Valley 90 years ago, but now the Lyell Glacier, a modern remnant (in terms of a process) of the ancient glacier that created that valley. Yosemite National Park's boundaries, so carefully created to protect the resources in the park, failed to save Hetch Hetchy, and can't save its glaciers from human-induced rapid climate change.

Only we can do that. And that.