Hidden beneath dense covers of rock and boulders in mountainous regions worldwide, more than 51,000 documented rock glaciers hold massive amounts of water ice, according to a study published in the Journal of Geophysical Research: Earth Surface. Researchers have developed a new 3D imaging method using gravimeters and Bayesian statistics to quantify these hidden reserves, revealing that Utah alone holds approximately 1 billion tons of ice within such formations.
How Researchers Measured Hidden Ice Beneath Mount Timpanogos
Studying rock glaciers has historically proved difficult because conventional ground-penetrating radar fails when rocky debris mixes with ice, scattering radio waves and ruining image quality. To solve this, University of Utah geology graduate student Bronson Cvijanovich used a gravimeter to detect hidden masses underground at the Mount Timpanogos rock glacier in 2024, according to the study. “There is a large contrast in mass density between the rock that makes up Mount Timpanogos and the much lower-density ice that is in the rock glacier adjacent to it,” explains co-author and geophysicist Michael Thorne. When the team measured gravitational acceleration over the rock glacier, they observed larger decreases in areas with thicker ice.
Global and Regional Ice Volume Estimates Revealed
After taking 232 measurements around the Timpanogos Glacier, researchers applied Bayesian statistics and modeling techniques to reconstruct the glacier’s thickness, shape, and composition. The findings show that the Timpanogos rock glacier consists of roughly 83 percent ice and 17 percent rocky debris by volume, with an average ice thickness of 18.8 meters, or 61.7 feet. This single landform contains about 1.5 million cubic meters of ice—roughly equivalent to the volume of the Great Pyramid of Giza—amounting to 1.4 million metric tons. By scaling these findings with surface area measurements from previous studies, the research team calculated that Utah’s 836 documented rock glaciers hold about 1 gigaton of ice. The western United States contains nearly 12 billion tons, while global rock glaciers store an estimated 48 billion tons of ice.
Did you know? Walkers high in the mountains often traverse loose rocks without realizing there can be up to 120 feet of ice buried directly beneath their feet, according to University of Utah glaciologist Leif Anderson.
Why Quantifying Rock Glaciers Matters for Climate Change
As global temperatures rise, traditional glaciers are responding to climate change by transitioning to debris-covered glaciers and ultimately rock glaciers, the study’s authors note. During periods of warming, these rock formations can become destabilized and pose direct threats to downstream infrastructure. Modeling these landforms in three dimensions helps scientists quantify essential water stores and map internal structures, allowing researchers to better constrain their impacts on local hydrology, ecology, and natural hazards.
Frequently Asked Questions
What is a rock glacier?
Rock glaciers are landforms in mountain regions where masses of ice and rock coexist, hidden under a hard surface layer of rock and boulders.
Why can’t scientists use radar on rock glaciers?
Conventional ground-penetrating radar is ineffective because rocky debris mixed within the ice scatters radio waves and severely degrades image quality.
How much ice do rock glaciers hold globally?
According to the study published in the Journal of Geophysical Research: Earth Surface, there is approximately 48 billion tons of ice stored inside rock glaciers worldwide.
What are your thoughts on these hidden ice reserves? Share your perspective in the comments below, or explore our latest science news coverage for more discoveries on Earth’s changing climate.
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