A new study from Portland State University suggests that some of the Mountain West鈥檚 most famous glaciers do not qualify as glaciers anymore.
This study defines a glacier as being present for more than 20 years, having an area of at least two football fields (or 0.01 square kilometers), and showing signs of movement. Without these, it鈥檚 just a perennial snowpack or a pile of rocks.
鈥淚f we saw crevasses, then we knew it was moving because cracks develop when the ice stresses and strains, said Andrew Fountain, professor emeritus at the university and one of the study鈥檚 authors. 鈥淓ven though the glaciers might have snow, the one that doesn't move is a snow patch or an ice patch, and the other with crevasses is by definition a glacier.鈥�
Researchers looked at U.S. Department of Agriculture aerial photos taken from 2013 to 2020 of about 4,000 areas, according to Fountain. They were only able to classify around 1,300 areas as glaciers and 1,200 areas as perennial snowpacks.
St. Mary鈥檚 Glacier in Colorado is too small and does not meet the 0.01 square kilometer threshold. Taylor Glacier in Rocky Mountain National Park is too rocky and does not have enough snow coverage to be a glacier. Isabelle, Moomaw and Peck Glaciers were all deemed perennial snowpacks.
Other well-known glaciers that didn鈥檛 make the cut in the Mountain West were Petersen Glacier in Wyoming and the Grasshopper Glacier in Montana. They don鈥檛 believe Idaho has any glaciers.
Their findings were last month.
Before this study, several paper topographical maps categorized areas as glaciers, but modern satellites and aerial photography hadn鈥檛 been used to track changes to them. Some of these maps were more than 30 years old.
鈥淕laciers in the western U.S. never had really been properly inventoried,鈥� Fountain said. 鈥淎s we know, glaciers have changed a lot since then (in 30 years)."
Researchers believe these glaciers are shrinking due to global warming 鈥� and possibly wildfires. Additionally, caverns in the glacier created by streamflow underneath can let sunlight in and melt the glacier.
鈥淪maller glaciers don't do as well, don't add as much water,鈥� he said. 鈥淎s glaciers shrink, these streams then become more and more susceptible to drought, as well as the surrounding riparian areas and adjacent landscapes, which changes the ecology in these high alpine areas.鈥�
One solution could be made by underground pipes that spray like fountains and freeze into a cone shape, which slows the melting. Another is , usually made of plastics and fleece, to help insulate a glacier and block the sun.
Fountain said that these 鈥渟top-gap measure[s]鈥� are 鈥渘ot going to be of practical value鈥� for the West. Instead, he wants people to focus on getting rid of the carbon dioxide to help slow global warming.
Despite this, . Some glaciers have endured due to their positioning away from the sun and extra shade coming from the shadow of nearby mountains 鈥� and if they get more snow than expected, that鈥檚 even better. Andrews Glacier in Colorado came to mind as an example.
鈥淭hose glaciers in those nice little basins having additional snow either by wind drift, travel, entering, sort of become climate insensitive because these other effects are kind of keeping that glacier intact,鈥� he said. 鈥淎ll of the glaciers, I think, in the front range should be gone by now, except these additional processes that keep them alive.鈥�
For his next research project, Fountain is trying to quantify how much water and ice has been lost.
This story was produced by the Mountain West News Bureau, a collaboration between Wyoming Public Media, Nevada Public Radio, Boise State Public Radio in Idaho, KUNR in Nevada, 萝莉少女 in Colorado and KANW in New Mexico, with support from affiliate stations across the region. Funding for the Mountain West News Bureau is provided in part by the .
