Middle Teton melting faster than it is gaining

GRAND TETON NATIONAL PARK — An annual glacier surface elevation survey conducted by scientists in Grand Teton National Park determined that the Middle Teton Glacier is overall melting faster than it is gaining — a sensitive indicator of climate change, park officials say.

Grand Teton National Park said that in 2021 alone, park scientists found overall glacial thinning with up to 6.3 meters of ice loss from the GPS survey.

Every year in late summer, park scientists coordinate with the Jenny Lake Climbing Rangers to survey the glacier’s surface elevation. Scientists record glacial surface elevations by walking with GPS devices attached to survey rods. Surveyors carefully walk on steep and wet glacial ice to pre-determined locations to record their data with centimeter accuracy.

“Between 2016 and 2021, the surveyed area of Middle Teton Glacier saw an average of about 1.6 meters of ice loss, with up to about 4.8 meters of loss in some places,” said the park. “This equates to a minimum loss of roughly 50,000 tons of ice or nearly 900 swimming pools worth of water over the five-year study. Thus, Grand Teton’s glaciers are shrinking quickly and future predictions on climatic shifts in the Greater Yellowstone Area don’t indicate a return to glacial glory anytime soon.”

Using data from this survey and previous spring surveys, scientists quantify the glacier’s balance (i.e., gain vs. melt) over a given year and compare it against previous years.

According to the park, glaciers are sensitive indicators of climate change.

“They respond to both temperature and precipitation. All glaciers in the park have retreated since the late 1800s, although there have been brief periods of advance, most notably the mid-1970s to mid-1980s.”

Fritiof Fryxell conducted the first survey of the Teton glaciers in the late 1920s and 1930s, and studies continued sporadically through the 20th century. Historic photographs show the extent of these glaciers as early as 1924, and scientists can trace glacial retreat using ground and aerial photos over the last 90 years. 

To learn more about the park’s monitoring program and to view a timelapse of the Middle Teton Glacier from June to September 2022, click here.

This article was originally published on Buckrail News in October 2022.