A mountain of loose rock in Utah holds enough ice to fill 600 Olympic swimming pools. This discovery shows that some of Utah's biggest frozen water reserves are almost invisible.
Unlike regular glaciers, which show large areas of ice, rock glaciers look like slow-moving fields of broken stone. Their rocky tops hide thick ice and protect it from sunlight and warm air.
These formations are common in Utah's Wasatch and Uinta mountain ranges. They also appear in the La Sal Mountains near Moab. One of the largest is under Mount Timpanogos, a peak near Salt Lake City and Provo.
We're a new kind of news feed.
Regular news is designed to drain you. We're a non-profit built to restore you. Every story we publish is scored for impact, progress, and hope.
Start Your News DetoxHidden Ice Beneath Mount Timpanogos
Two studies from the University of Utah have revealed how the Timpanogos Rock Glacier formed. They also found out how much frozen water it contains. Researchers estimate that ice makes up 83% of the formation. Loose rock accounts for the other 17%.
This buried ice holds about 1.5 million cubic meters (53 million cubic feet) of water. This amount could fill 600 Olympic swimming pools. It is similar in size to the largest pyramid in Giza, Egypt. This information comes from Bronson Cvijanovich, a former graduate student.
"Timpanogos Rock Glacier is surprisingly rich in ice," said Cvijanovich. He was the lead author of one study. It was done with geophysics professor Michael Thorne and glaciology professor Leif Anderson.
Anderson added, "There's a lot of ice hidden in Utah's mountains. When we walk across loose rocks high in the mountains, we don't realize there could be 120 feet of ice buried below."
Mapping Ice With Gravity
Because the ice is hidden, researchers cannot measure it with normal surface observations. Satellite images can show where a rock glacier is. However, they don't reveal much about the depth, shape, or volume of the frozen material inside.
Cvijanovich led six trips to Timpanogos Rock Glacier in the fall of 2024. He carried sensitive instruments to the formation above Emerald Lake. He used a special gravimeter to take readings at 232 points. Each point was 25 meters (about 80 feet) apart.
This method uses a basic physical difference: ice is much less dense than rock. Areas with thicker ice pull slightly less with gravity. This allows scientists to map the buried ice without drilling into it.
"There is a big difference in density between the rock of Mount Timpanogos and the much lighter ice in the rock glacier next to it," Thorne explained. "When we measure gravity over the rock glacier, we see a larger drop in gravity over areas with thicker ice."
A Three-Dimensional View Underground
The measurements needed careful adjustments. Gravity changes with elevation, location, surrounding land, and even the sun and moon. After accounting for these factors, the team used statistics to figure out the most likely 3D shape of the hidden ice.
"We spent months of computer time doing the imaging with our new methods," Thorne said.
The result is like a CT scan of a human body. Instead of using radiation to show bones and tissues, this method uses tiny changes in gravity. It maps ice buried under a thick layer of rocky debris.
This technique could help scientists estimate the contents of other rock glaciers. Many are too remote or unstable to drill into. It also reveals a part of the mountain water system that traditional glacier surveys often miss.
How Utah’s Rock Glaciers Formed
Rock glaciers often form in steep valleys or cirques. Here, erosion causes rocks to fall onto snow that stays frozen. As debris builds up, it buries the snow. This helps protect the ice that forms from the environment.
"In the Wasatch, the mountains themselves are eroding and burying the snow. That's why the rock glaciers exist," Anderson noted.
The researchers created a mathematical model to describe this process. It shows how rockfalls add mass to a rock glacier. They cover long-lasting snow in its upper parts. This gradually builds an ice-rich mixture under a rocky surface.
The second study found that Utah's rock glaciers are not direct leftovers from the Ice Age. That period peaked 21,000 to 18,000 years ago. Instead, they formed thousands of years after the region's ancient glaciers disappeared. This means they are younger frozen reservoirs, not old ice sheets.
A Global Reserve of Frozen Water
Satellite surveys have found 836 rock glaciers in Utah alone. The researchers used the relationship between surface area and ice volume measured at Timpanogos. This helped them estimate how much ice might be hidden in other formations.
When applied to the about 50,000 known rock glaciers worldwide, this calculation suggests they store about 48 gigatons of water. One gigaton is 1 billion metric tons. This is about one cubic kilometer (0.24 cubic miles) of water, enough to fill 400,000 Olympic swimming pools. Utah's rock glaciers may contain about 1 gigaton of water, which is 815,000 acre-feet.
Deep Dive & References
The Internal Ice Content of Timpanogos Rock Glacier, Utah, USA From 3-D Bayesian Inversion of Gravity Data - Journal of Geophysical Research: Earth Surface, 2026
