Warming of the climate system is unequivocal, as is evident from observations of increases in global average air and ocean temperatures, widespread melting of snow and ice and rising global average sea level. (Intergovernmental Panel on Climate Change, 2007).
This quote, shared by my global climate change professor, hung heavily during the last course of the semester. No ifs, ands, or buts about it: global temperatures are rising causing snow and ice to melt. Unfortunately, anthropogenic greenhouse gas emissions and resulting climate warming are not predicted to slow down based on existing models. So how do snow and ice, that make up the glaciers in Grand Teton National Park, respond to the changing climate?
Shortly after graduating, I joined the Physical Science Program in Grand Teton National Park where we seek to answer that question. Grand Teton National Park is home to 11 named glaciers. Glaciers form where snow accumulates, compacts, and recrystallizes into dense ice that moves under its own weight. These glaciers are critical freshwater reserves, especially in late summer when seasonal snow has already melted. Middle Teton Glacier (MTG) is one of these 11 glaciers. MTG is a benchmark glacier (i.e., it is representative of other glaciers in the Teton Range) and is the primary focus of our monitoring efforts here in the park.
Monitoring of MTG by park staff began in 2014. Our monitoring plan includes measuring glacial volume and tracking glacial movements, a process that starts in late spring at the end of the snow accumulation season. At the glacier, we probe the snow and ice, record snow densities and depths, and install ablation (A.K.A. “melt”) stakes. These stakes are comprised of several marked PVC pipes connected inside by a string and are steam-drilled into the glacial surface. As the summer progresses and the glacial surface melts, the PVC pipes move downslope and become exposed. We track the movement of the stakes with GPS devices and record the length of PVC pipe exposed each month. In late summer, we coordinate with the Jenny Lake Climbing Rangers to survey the glacier’s surface elevation. Using data from the ablation stakes and elevation surveys, we can quantify the glacier’s balance (i.e., gain vs. melt) over a given year and compare against previous years.
Monitoring MTG is no easy task. Our late summer fieldwork on the glacier requires detailed preparation: organizing our field crew, testing field equipment, packing our bags with food and supplies for 2–3 days in the backcountry, and checking weather forecasts. Weather permitting, we hike 5,000 vertical feet in five miles while carrying 30–50 lbs. backpacks. At the glacier, we attach GPS devices to three-meter survey rods; carefully walk on the steep, wet glacial ice to pre-determined locations; and record glacial surface elevations to centimeter accuracy. After surveying for several hours, we pack up our equipment and move to camp in the high country. We rise early and return to the glacier the next day to continue the survey. In total, the survey takes two or three field days and an additional week in the office to process data.
Even with extensive preparation, we inevitably face serious challenges during glacial fieldwork such as equipment failure or rockfall. During an early-spring visit, crews began steam-drilling an ablation stake hole in the glacier, but the drill bit and hose froze in the ice. Recovery efforts for the drill were unsuccessful, delaying fieldwork until we could purchase new equipment. To mitigate rockfall risks, we start early (when temperatures are cool and before ice starts to melt), wear helmets, and designate a spotter while others survey. However, during a late summer survey, glacial melting dislodged a couple microwave-sized boulders that tumbled towards our field crew. Our spotter warned the crew members in time to run out of the way and avoid the falling boulders. With a clearly defined and regularly practiced safety plan, we reduce risk as much as possible while collecting valuable data on the state of the park’s glaciers.
Unfortunately, as expected, the data confirms that MTG is overall melting faster than it is gaining. In 2021 alone, our team calculated 2–5 meters of ice loss from the ablation stakes and found overall glacial thinning (up to 6.3 meters of ice loss) from the GPS survey. This ice, which took generations to form, was gone in 3 months with little chance of coming back: If this rate of melting continues, it is possible that MTG will cease to exist in my lifetime. The remnants of the incredible glaciers that shaped the Teton Range will disappear, forever altering the natural, cultural, and scenic characteristics of the Tetons.
After reading these results, my colleagues and I left the office overcome with sadness. We bought ice cream at Dornan’s, sat on a bench and ate in silence. How do we scientists, reading these results within the confines of our office cubicle, process the questions that come with the disheartening results of our hard work? How are we to preserve these glaciers for the enjoyment, education, and inspiration of current and future generations?
Joni Gore, Hydrologist
Last updated: March 29, 2023