Every summer for the last three years, Jukes Liu, a Boise State graduate student working on the third year of her Ph.D. in the Department of Geosciences, flies 1,892 miles to the small fishing town of Yakutat, Alaska, to study the most temperamental glacier on the planet.
Sít’ Kusá (“narrow glacier” in the native Tlingit language) is part of a small family of glaciers called surging glaciers. Their defining trait is a speed cycle; they have a long period of traveling slowly, and then a shorter period of traveling quickly.
“These glaciers are really rare,” Liu said. “Only about 1% of the world’s glaciers exhibit this oscillating behavior between slow and fast, and ours has the shortest known surge cycle in the world with two years of fast speeds and six years of slow speeds.”
In slow mode this glacier travels about 1 foot per day, while in fast mode it travels up to 100 feet per day.
Sít’ Kusá is an ideal subject of study because the faster cycle allows the scientists to see the whole cycle in a shorter amount of time. Despite being the ideal subject, there is remarkably little research on the glacier, that’s where Liu and her colleagues come in.
The project was funded in 2020 by the National Science Foundation, and in August of that year, the team went to Sít’ Kusá for the first time to learn how and why this surging effect happens.
The project is a collaboration between Liu and assistant professor of geosciences Ellyn Enderlin at Boise State, with Yoram Terleth and Dr. Tim Bartholomaus at the University of Idaho. Liu is studying the motion of the glacier while Terleth is studying seismology.
“The work Jukes has been doing is really important because she is making these custom maps of a surging glacier that are way more detailed than anything we’ve been able to get of a surging glacier before,” Enderlin said. “It is giving us great insights of what is causing these glaciers to surge.”
Liu’s team places remote sensory equipment that can monitor and take pictures of the motion, composition and seismography of the glacier and the surrounding area. This is all being used to make graphs and maps to better understand how and why this glacier, and other surging glaciers, do what they do.
Photo courtesy of Tim Bartholomaus
The locations where the team needs to place the equipment are spread out over many crevasses so they rely on a local pilot to fly them to different points of the glacier.
“I should also mention that it snows a lot here, like 20 feet plus per year,” Liu said. “At some point all of our equipment gets completely buried by snow. Every time we come back up our stations are in need of repair.”
That is not the only danger that the equipment faces. According to Liu, on the lower instrumentation sites, the equipment often gets visited by bears that use them as scratching posts and even leave behind fur. In their curiosity, they will sometimes even rip them out of the ground. Between the snow, bears and other problems, instruments have fallen into the crevasses never to be seen again.
“Weather can change quickly when we are on the glacier, too,” Liu said. “The cloud ceiling can drop and we get ‘socked in,’ then the pilot can’t get to us and we just have to wait out there and hope the weather improves.”
According to Liu and her research so far, the glacier also accumulates mass at the higher part of the glacier during the slow period. The build up hits a threshold that triggers the surge, this appears to be a trait of all surging glaciers.
The high and long lasting change is mostly a case of friction. Different bedrock compositions underneath the glacier provide different levels of resistance, and pools of water can also form between the glacier and the rock during warm seasons, creating a Slip ‘N Slide effect, the same way that roads are more slippery when wet.
This is a highly shortened explanation of a much more complex and nuanced set of diagrams, maps, and other data collected by Liu and her team.
“Her math and technical skills are fantastic,” Enderlin said. “I usually meet with my graduate students every week and it’s more like speaking to a colleague than a student. I know more about glaciers but she has far more technical skills than I do and she often actually teaches me about how to use and interpret the tools that she is using.”
It is important to note that Liu also has a fellowship with NASA that helps fund the compilation and supplementation of the remote sensing data as well as satellite imagery.
“It’s awesome to be out there,” said Liu. “It is like nowhere else I’ve been. It’s kind of like going back in time because it’s so isolated. It rains so much; I’m from Seattle and I thought that was rainy but it doesn’t even compare. But on the days that it is sunny, it is absolutely gorgeous and you can even see Mount Saint Elias. It really is a hidden gem.”
Liu is in the third year of the project, and at the end of the fourth year she will present her impressive findings to earn her doctorate degree from Boise State University.
