Kathy Mellander knew Grand Teton National Park’s glaciers were melting. The park GIS specialist and hydrologist had read studies published in 2012 and seen historical pictures that showed the park’s 12 glaciers used to be much larger than they are today.
Previous studies estimated the park lost 40 percent to 55 percent of its glacier mass during the last 60 years. Mellander knew average temperatures have been rising, and she’d seen data from other areas where glaciers are receding. But her visit to the park’s Schoolroom Glacier on Aug. 13 shocked her. She saw exposed ice she’d never seen before.
“Wow,” Mellander said. “It’s happening very fast.”
Mellander didn’t take an official survey that day, but said, anecdotally, the glacier looked much smaller than when she’d seen it last. Crevasses had opened up that hadn’t been there the summer before, and the glacier margin — the line at the bottom of the snow — had receded enough to be noticeable at a glance.
The park is working on gathering more than observational evidence of its glacier decline.
In 2012 Grand Teton National Park launched a program to quantitatively monitor the Schoolroom, Middle Teton and Petersen glaciers. Researchers began by trying to figure out the best way to study the glaciers and the role of the changing climate. They settled on monitoring several glaciers by documenting their size with high-accuracy GPS units and installing time-lapse cameras to document change.
The Jenny Lake Climbing Rangers assist in the monitoring, using GPS to chart points on the glaciers. It provides accurate elevation data and allows Mellander to see the exact size of the glaciers. This summer the rangers surveyed the Middle Teton glacier to gather baseline data. They surveyed Schoolroom Glacier in 2013. The plan is to alternate each year between surveying the Schoolroom and Middle Teton glaciers and compare changes in size to the initial measurements gathered.
Petersen Glacier, situated north of Cascade Canyon, is mostly under rock. Mellander will monitor it by measuring its annual runoff using a waterflow device. The rock layer on top of the glacier insulates it from higher temperatures and solar radiation, so it is likely declining at a slower rate than other glaciers in the area, she said.
The three glaciers currently targeted for research were chosen in part because of accessibility. While the Teton glacier is iconic, rockfall in the area makes it too dangerous for on-site monitoring.
Mellander said she expects to see some measurable change from year to year, but it will take several years to see major changes. However, after the noticeable difference in size Mellander observed on Schoolroom Glacier this summer, one summer of footage might show year-to-year shrinking.
The park installed several thermometers at higher elevations this summer to provide a more accurate picture of what is happening weather-wise at the glacier sites. Researchers collect snowpack and temperature data that will be compared to data on glacier recession to provide an overview of the climate and its effect on the glaciers.
“The biggest lesson we’ve learned so far is there is incredible variation,” Mellander said.
This spring, snow melted three weeks earlier than the year before. That degree of variation means glaciers may also grow temporarily. There still may be years when there is a lot of snow that never fully melts but instead becomes denser and eventually adds to the glacier’s ice mass. These expansions are usually temporary and slower than the recession of other years, but it’s why the long-term data is so important, Mellander said.
The data will be shared with monitoring groups that are tracking glaciers around the world. Scientists will compare the data from Grand Teton National Park with other areas in the West like the Cascade Mountains. “It will be another piece of the global puzzle looking at overall changes in glaciers around the world,” Mellander said.
There are 12 named glaciers in Grand Teton National Park, but they might not all technically be glaciers anymore. Glaciers are defined by movement and some of these glaciers may have turned to permanent snowpatches, no longer big enough for gravity to pull them downhill, said Ann Mattson with the park’s division of interpretation.
The biggest function the glaciers serve is providing a cold, late season run-off, Mattson said.
Without that cold water, stream temperatures rise and impact fish and other aquatic life. Not only can it make it hard for native species to survive, temperature changes can help invasive non-native species thrive.
“Without that cold glacial runoff, or if there is less, it just weakens the entire ecosystem,” she said.
Glaciers are also iconic features of the park.
“They are very much a part of the visitor experience here as the peaks themselves,” Mellander said.
Now that the park has a plan for monitoring the glaciers, staff will reach out to volunteers to help record observations. Mellander hopes to involve the general public as well as the climbing community.