A rocky mountainside in Utah is hiding a giant block of ice that makes up 83% of its volume, enough frozen water to fill 600 Olympic swimming pools. Researchers at the University of Utah used gravity measurements to create a 3D map of the buried glacier beneath Mount Timpanogos, revealing a vast store of water that no one could see from the surface.
A glacier that looks like a pile of rocks
Rock glaciers look nothing like the icy rivers most people picture. They appear as sprawling fields of loose rubble, but beneath that rocky exterior, they can conceal massive amounts of ice. The Timpanogos Rock Glacier, located near Salt Lake City and Provo, is one of the largest examples in Utah's Wasatch and Uinta ranges. Similar formations also exist on the Colorado Plateau in the La Sal Mountains near Moab.
Measuring gravity to find hidden ice
During the fall of 2024, former graduate student Bronson Cvijanovich led six field trips to the glacier above Emerald Lake, carrying a state-of-the-art gravimeter. The device detects tiny differences in gravitational pull caused by density variations, allowing the team to distinguish the denser surrounding rock from the lighter buried ice. They collected measurements at 232 points spaced 25 meters apart, then used the data to estimate the glacier's shape and thickness.
The results, published in two new studies, show the Timpanogos Rock Glacier holds about 1.5 million cubic meters of frozen water. That is roughly the same volume as the largest pyramid at Giza in Egypt. The glacier is 83% ice and 17% loose rock, according to Cvijanovich, who worked under geophysics professor Michael Thorne and glaciology professor Leif Anderson.
Why this matters for Utah's water supply
Glaciology professor Leif Anderson said there is a lot of ice hidden in Utah's mountains. People walking across loose rocks or rubble high in the mountains may not realize there could be 120 feet of ice buried beneath their feet. The findings suggest rock glaciers form when falling debris buries persistent snow, preserving it for thousands of years. Similar formations around the world may collectively store tens of gigatons of hidden water, making them an overlooked but potentially significant source of frozen freshwater.
The discovery at Mount Timpanogos offers a new way to study these hidden reservoirs. By using gravity measurements to map the interior of rock glaciers, scientists can better understand where water is stored in mountainous regions. This technique could be applied to other sites, helping researchers assess how much ice is actually locked away in rocky landscapes across the globe.
