Researchers at the University of Utah have discovered 1.5 million cubic meters of ice buried beneath loose rock on Mount Timpanogos, mapping the hidden reservoir using 232 precise gravity readings collected during the fall of 2024.
From a distance, the Timpanogos Rock Glacier looks like a sprawling, unremarkable field of rubble high in Utah’s Wasatch Range. But new research reveals a sprawling underground storage facility: a thick mantle of loose rock concealing a massive core of frozen water.
Mapping the Mountain With 232 Gravity Readings
To uncover what lay beneath the stones, geologists executed a demanding field campaign. In the fall of 2024, former geology graduate student Bronson Cvijanovich led six trips up a rigorous five-mile trail with an elevation gain of 3,500 feet to reach the site above Emerald Lake, hauling a state-of-the-art gravimeter across the terrain (according to the University of Utah).
The team gathered data at 232 distinct locations, spaced roughly 25 meters apart in a grid pattern. Gravimeters detect subtle differences in density, allowing scientists to separate the heavy rock surrounding the landscape from the much lighter ice hidden underneath. Because rock is denser than ice, areas with thicker underground ice register a slightly weaker gravitational pull. After accounting for terrain, elevation, latitude, and the gravitational pull of the sun and moon, the researchers ran months of computation using Bayesian statistical modeling to build a 3D image of the glacier’s interior (as reported by the Times of India).
“Timpanogos Rock Glacier is surprisingly ice rich. It is 83% ice and 17% loose rock.”
Bronson Cvijanovich, former graduate student in the Department of Geology & Geophysics
That density contrast produced stark results. At its thickest point, the buried ice reaches roughly 150 feet below the surface. The total volume of 1.5 million cubic meters of frozen water is roughly equivalent to the volume of the largest pyramid at Giza in Egypt, or enough liquid to fill about 600 Olympic-sized swimming pools (Science Daily detailed in its release).
How Erosion and Rockfalls Feed the Wasatch Ice
Understanding how a massive ice body survives underneath a blanket of baking surface rock has long puzzled geologists. The research team developed a new mathematical model to explain the formation, concluding that eroding mountain slopes regularly shed debris onto persistent snow patches in high-altitude cirques.
“In the Wasatch, the mountains themselves are eroding and burying the snow, and that’s why the rock glaciers exist.”
Leif Anderson, glaciology professor
Instead of being lingering relics from the peak of the Ice Age 18,000 to 21,000 years ago, these rock glaciers developed during the millennia that followed as rockfalls repeatedly covered and insulated persistent snow. Years marked by heavy snowfall, cool summers, and substantial rockfalls directly contribute to this hidden accumulation.
Global Implications for Mountain Water Reserves
While Mount Timpanogos is just one of 836 rock glaciers cataloged across Utah via satellite imagery, the implications stretch far beyond state lines. By establishing a direct mathematical relationship between a rock glacier’s surface footprint and its subsurface ice volume, the team estimated that roughly 50,000 known rock glaciers worldwide contain approximately 48 gigatons of water.
For an arid state like Utah, where rock glaciers collectively store an estimated one gigaton of water, these insulated reserves offer a distinct buffer against warming climates. The surface layer of rock shields the frozen core from direct solar radiation and ambient heat. While some rock glaciers have already lost their ice cores, active formations like Timpanogos continue to store vital reserves right beneath the boots of unsuspecting hikers.
