U. researchers find possible water source in Mount Timpanogos rock glacier

SALT LAKE CITY — New research methods are revealing how much water can be found buried in Utah's mountains, leading to an updated understanding of our water supply and knowledge of future hazards.

There is enough water in the Timpanogos Rock Glacier to fill 600 Olympic swimming pools, according to new research by University of Utah geologists.

How could this be? Geophysicist Michael Thorne says Timpanogos hikers likely wouldn't have known they stood on top of a glacier, because it's covered in rocks, gravel and debris.

"We suspect that there's ice under many of them," Thorne said. "And as you're looking from the surface, you can see these features, you can measure how large they are on the surface. But what we can't do is tell how much ice, how thick the ice is underneath them."

In many cases rock glaciers are just that — only rocks, and any ice has melted away, leaving only a rock-filled slope.

How they did it

It was only since Thorne and glaciologist Lief Anderson teamed up that we now know there is a body of ice up to 150 feet thick located right above Emerald Lake. Thorne and former graduate student Bronson Cvijanovich worked for a semester on the mountain, testing different devices and measuring methods before they found one that worked. Using "really, really precise" gravitational acceleration, they created a 3D image of the ice body.

"If you go from measuring gravitational acceleration over rock — like over the rock that makes up Mount Timpanogos, it has greater mass, greater density. But then if I walk over an area that has thicker ice, that ice has less density than the rock. So the gravitational acceleration that we measure is actually less. And so then we can do this modeling," Anderson said. "That's part of what we did in this study, is develop a new way of doing the modeling to determine then from these measurements of the gravitational acceleration: This is how thick the ice is beneath us."

The ice is covered by rock and debris, and each year Anderson says snow falls, which is then covered in debris and rock slides, leading to slow but steady growth of the glacier over time. Anderson says the presence of these ice-filled rock glaciers can be good news for Utah.

Firstly, because the glacier can be good for arid, dry climates like Utah where rock glacier ice melts more slowly than an exposed glacier would.

"That melt occurs in the summer after all or most of the snow, for example, in the Wasatch or the Uinta has melted away," Anderson said. "The rock glaciers are providing a sort of a sustained late summer flow into streams and then also into the groundwater. And so that can be an important contribution to the watershed."

Second, since the ice is covered, its melted water is much cooler and can bring important ecological benefits to cold water species.

However, events like the catastrophic flooding in Nepal highlight the danger of these hidden hazards.

"It's a horrible tragedy what's happened in Nepal," Anderson said. "And I know there's a lot of people who have been researching hazards in like high tectonic places, like the Himalaya or the Wasatch, and how it relates to sort of, earthquakes and glaciers and, also debris and rocks."

As climates warm, Anderson says geologists are seeing more glaciers retracting, picking up and being covered by debris.

"We are also seeing an increase in these really large catastrophic events related to the collapse of glaciers," Anderson said.

He doesn't expect these types of events to slow down anytime soon.

"You're changing the shapes of glaciers with climate change," he said. "They're shrinking, they're becoming, that will tend to lead to more unstable situations."

400,000 Olympic swimming pools

There are estimated to be around 836 rock glaciers in the state, with enough ice in them to fill 400,000 Olympic swimming pools.

"The ice also has the potential to store hidden water. So you can have lakes under glaciers," Anderson said, adding that there is continued work to identify more ice-filled rock glaciers in the state. "Right now, it seems like the most likely ones are around Mount Timpanogos. And then also in Little Cottonwood Canyon."

The Wasatch fault adds another layer.

"There's no doubt, right, that the Wasatch Front, the big hazard is the Wasatch fault and magnitude 7 earthquakes. And so whenever you shake mountains, things can fall. And another huge hazard here."

Anderson pointed to one in the Snowbird ski resort.

"There's a huge rock avalanche deposit that's 1000 years old," he said. "Farther up, there's one that's about 14,000 years old."

Anderson said the work the team has been doing can help them identify more of these ice-filled rock glaciers, most thought to be around Mount Timpanogos and Little Cottonwood Canyon, where massive amounts of snow build up on the steep mountains.

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