Heatwaves, climate change pushing Central Oregon glaciers closer to extinction

February 7, 2022
Heatwaves, climate change pushing Central Oregon glaciers closer to extinction

Several small glaciers near Broken Top, South Sister on brink of extinction

By Michael Kohn

A succession of heat waves last summer that caused heat-related deaths, dried up crops and depleted snowpack may have also accelerated the disappearance of Central Oregon glaciers.

Five glaciers that were already in danger of melting out may have thinned to the point where they no longer qualify as glaciers, according to Anders Carlson, president of the Oregon Glacier Institute. The glaciers are part of a group of 13 glaciers that remain in the Central Oregon Cascades.

Glaciers play an important role in Central Oregon’s ecology, providing late-season snowmelt that keeps streams and rivers flowing year-round, benefiting fish and wildlife. Glaciers also help keep forests cool and moist, helping to reduce the threat of wildfire.Late season melt is also important for farmers who depend on consistent runoff for their crops. Carlson said global warming and the loss of the glaciers will have dire consequences for Central Oregon’s agricultural communities.

“If one wants to farm and ranch like the 1950s, one needs the atmosphere of the 1950s,” said Carlson. “That atmosphere will sustain glaciers and the waters that sustain economies of Central Oregon.”

Snow surveys conducted in the 1950s identified 30 glaciers in the Central Oregon Cascades. Precisely how many remain after last summer’s heat wave is unclear and more research next summer is needed, said Carlson.

“Almost three-fourths of Central Oregon’s glaciers could be stagnant or gone,” he said.

The loss of ice from Central Oregon glaciers is not a recent phenomenon. Photographic evidence shows that Collier Glacier on North Sister had already retreated significantly between the 1920s and the 1950s.

New photos show that the glacier retreat has continued unabated in recent years. Jim O’Connor, a U.S. Geological Survey geologist who visited the glacier last year, said the ice waning and the lake that once stood at the snout of the glacier are completely gone.

“It is sad in many ways,” said O’Connor. “Last year was the driest I have ever seen it up there going back to 1991.”The weather conditions depleting the glaciers have been record-setting.

Last year was the hottest on record in Oregon, with an average temperature of 67.7 degrees, according to Larry O’Neill, an associate professor at Oregon State University’s College of Earth, Ocean and Atmospheric Sciences. Average temperatures in the 1900s were 5.5 degrees cooler than the summer of 2021, he said.

The warming temperatures are depleting glaciers elsewhere in the state too. Andrew Fountain, a professor of geography and geology at Portland State University, says all the glaciers in the Wallowas are now gone. The last remaining glacier, Benson Glacier, named after an early Oregon governor, has withered away in recent years.

All that remains are some patches of ice less than the size of a football field, said Fountain.

The climate situation isn’t much better this winter either. Despite a series of powerful winter storms in late December and early January, which briefly sent Central Oregon snowpack well above average, snowpack is below average again.

Snowpack has fallen to 96% of normal in the Upper Deschutes and Crooked River basin, according to data compiled by the Natural Resources Conservation Service. Precipitation for this water year is just 92% of normal.

O’Neill worries that if the snowfall doesn’t pick up and the region finishes the year with average numbers, this summer’s water supply issues will be worse than in 2021, accelerating a multi-year drought.

From a historical vantage point, the drought has been one for the ages.

“Many of the drought indicators suggest the last two years have cumulatively been the worst drought for Central Oregon in recorded history,” said O’Neill. “That’s going back to 1895.”

Carlson and other researchers are already planning visits to the glaciers next summer for further evaluation. In particular, Carlson is most concerned about the fate of three glaciers on South Sister (North Skinner, Skinner, and Carver). Two glaciers on Broken Top (Crook and Bend) are also at risk.

“Some of them still have ice left, but they are just stagnant,” said Carlson. “The carcass of the glacier is melting away on the landscape.”

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