Utah's hidden mountain glaciers hold billions of tons of water, study reveals

Beneath the loose rubble of Mount Timpanogos, hidden from anyone walking across its surface, lies an enormous reservoir of ice. University of Utah researchers recently mapped this buried glacier in three dimensions using gravity measurements and discovered something striking: the Timpanogos Rock Glacier is 83% ice, containing about 1.5 million cubic meters of frozen water—enough to fill roughly 600 Olympic swimming pools, or roughly the volume of Egypt's largest pyramid.

The discovery emerged from fieldwork conducted in fall 2024, when Bronson Cvijanovich, a graduate student in the Department of Geology & Geophysics, made six trips to the glacier above Emerald Lake carrying sensitive equipment. At 232 locations arranged in a grid across the ice, spaced 25 meters apart, he collected gravity measurements using a state-of-the-art gravimeter. The instrument works by detecting minute differences in density—rock is far denser than ice, so areas with thicker buried ice produce a measurable decrease in gravitational acceleration. After accounting for subtle variations caused by the sun and moon's positions, terrain, latitude, and elevation, the research team spent months using Bayesian statistics to reconstruct the glacier's internal structure in three dimensions. The result was a detailed map of what lies beneath the surface, something satellite imagery alone cannot reveal.

What makes this ice significant is how it formed. Rock glaciers in Utah's Wasatch Mountains develop in steep valleys where falling debris regularly accumulates. Rather than being remnants of the Ice Age—which peaked between 21,000 and 18,000 years ago—these formations are much younger. The mountains themselves are eroding, and that falling material buries persistent snow, protecting it from melting and preserving it for thousands of years. Leif Anderson, a glaciology professor involved in the research, noted the counterintuitive reality: when walking across loose rocks high in the mountains, a person might be standing atop 120 feet of buried ice without realizing it.

The implications extend far beyond Utah. Researchers identified 836 rock glaciers across the state through satellite imagery. Using the detailed measurements from Timpanogos, they established a relationship between a rock glacier's surface area and the volume of ice stored beneath it, then applied that relationship globally. Their calculations suggest that approximately 50,000 known rock glaciers around the world could collectively contain about 48 gigatons of water—equal to a cubic kilometer of water per gigaton, or enough to fill 400,000 Olympic swimming pools. Within Utah alone, rock glaciers may store about 1 gigaton of water, equivalent to roughly 815,000 acre-feet.

The research, overseen by geophysics professor Michael Thorne and published in the Journal of Geophysical Research on August 26, represents a new way of seeing what lies hidden in mountain terrain. As climate change alters precipitation patterns and temperatures across high-altitude regions, understanding the scale and distribution of these frozen reserves becomes increasingly important. The work suggests that mountains worldwide contain far more water than previously recognized—water locked in formations that most people walking past them would never suspect existed.