Science on sleds: Researchers measure shrinking of Beartooth glaciers

2012-10-03T00:00:00Z 2014-08-25T08:03:10Z Science on sleds: Researchers measure shrinking of Beartooth glaciersBRETT FRENCH french@billingsgazette.com The Billings Gazette

Sledding took on a new meaning for a group of Rocky Mountain College students this summer when they helped launch a plastic toboggan loaded with high-tech GPS gear down two Beartooth Mountains glaciers.

“We were trying to get a baseline on the thickness of the ice at the center,” said Jennifer Lyman, a Rocky professor of environmental sciences who has helped out on the two-year project.

The measurements were a way to ground-truth whether analysis of stereoscopic images was giving correct measurements. The work was funded by the Cinnabar Foundation and the Forest Service and was conducted in conjunction with the Absaroka-Beartooth Wilderness Foundation.

Lyman said she got the idea to use the sled after taking a group of students into Yellowstone. They brought along plastic sleds to play on the snowpack.

Lyman’s husband Tom, a field engineer for the National Science Foundation's Plate Boundary Observatory Project, designed the sled and installed the GPS system and electronics.

Rather than risk the safety of students or professors to climb down the steep glaciers to record data, the sled was tied onto 800-feet of 7mm mountain climbing rope and lowered down the glaciers.

“Sending the sled down worked great,” Lyman said, “but to pull it back up was really hard.”

That’s where the young, strong students helped. They included Aron Smethurst, Taylor Westhuesen, Zach Farrand, Robert Walker, Matt Dewitt and Sean Kenyon.

“We had really great kids who helped out and made it easier,” Lyman said. “We were afraid we were going to drop it in a crevasse or lake.”

Storied glacier

West Grasshopper Glacier, northeast of Iceberg Peak, and a glacier on the side of Mount Rearguard were chosen for the work. The data will add to a long history of research on West Grasshopper Glacier. (There is also an East Grasshopper Glacier.)

In 1898, James R. Kimble was mapping what would be named the Beartooth Mountains north of Cooke City when he saw Grasshopper Glacier. The well-known Hayden expedition, which explored Yellowstone and the surrounding region in 1878, had claimed there were no glaciers in the mountain range. Kimble corrected that mistake.

The photographer accompanying him, a Seattle-based Norwegian named Anders Beer Wilse, snapped a photograph of the bug-riddled ice and in time an 11,788-foot peak just to the southeast of the glacier was named after Wilse. He later became well-known for his photographs taken in Seattle during the Alaskan gold rush.

Maybe because of the grasshoppers encased in its ice, the glacier has been visited often and photographed repeatedly over the years, showing how much it has shrunk with time.

Why glaciers?

Glaciers are important for a couple of reasons. They provide meltwater that feeds streams in the summer after snowfields have disappeared. The water is used by irrigators, hydropower dams, cities, for drinking water, and anglers and floaters.

Another reason glaciers are important is that as they move downhill, they grind rocks into a fine sediment called glacier flour that, when carried downstream by the meltwater, provides nutrients for aquatic life. The flour is what gives glacial waters their milky look.

Throughout the world, glaciers have been shrinking as the spring and summer seasons have gotten longer and warmer, on average, than in recent history. West Grasshopper Glacier is no exception. Old photos show a huge mass in an area that now becomes a lake in summertime.

"In a couple of years, there's not going to be much of it left," said Tom Lyman. "It was melting like crazy this year. Of course, it was an exceptional year, but one more like that and it might be gone."

A glacier differs from a snowfield in several ways. The most obvious is that snowfields will sometimes melt completely in the summer. Glaciers are formed wherever more snow accumulates than is lost each year.

Glaciers also move as snow accumulates at the head of the glacier and is compacted under new snowfall, creating the dense ice found at the bottom. The weight of the ice pushes it downhill. Rocks imbedded in the ice grind over the mountainside rock, producing the glacial flour.

One of many

“Glacial ice and firn (granular, partially consolidated snow) in most areas of Montana’s Beartooth Mountains are melting at an astounding rate,” wrote the Rocky researchers, including Lyman and Rocky professor Luke Ward, in a paper on their work.

According to other research, there are about 400 glaciers and perennial snowfields in the Beartooth and Absaroka mountain ranges -- about one-third of the total number of such features found in Montana. It’s estimated that the total snow-covered area in Montana measures 42.6 square miles. Glacier National Park’s features are the most well-known in the state.

Although glaciers like those found in the Beartooths are small -- worldwide, they account for only 3 percent of the earth’s ice cover -- scientists estimate that their melting has contributed about 20 to 50 percent to the sea level’s 4- to 6-inch rise in the last century.

The Rocky Mountain College project will help track the two Montana glaciers’ growth and recession if similar work is repeated. The group also proved that their method is inexpensive and works well in remote mountain areas.

“In Greenland they’re using lasers to measure glaciers,” Jennifer Lyman said. “Ours is kind of the inexpensive technology.”

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