Avalanches are common in the Rocky Mountains. They can, and often do, occur in northern Utah.
“So, an avalanche is a tumbling mass of snow downhill, and you need four basic ingredients for an avalanche," said Eric Peitzsch, a research physical scientist with the U.S. Geological Survey at the Northern Rocky Mountain Science Center. "You need a weak layer, a slab on top of that weak layer. You need a sufficiently steep slope, and you need a trigger.”
He explains that common avalanche triggers come in many forms, from additional snowpack to snowmobilers, but these triggers differ by avalanche type.
“The triggers for a wet snow avalanche are typically warm, sunny periods of weather and rain on snow," said Peitzch. "And the difference between a wet and a dry avalanche is basically that having liquid water in the snowpack is necessary for a wet avalanche.”
Historically, wet snow avalanches are less studied than dry snow avalanches. This is due — at least in part — to the fact that they occur later in the season when warmer temperatures allow water to move rapidly through the snow.
“When that water interacts with that weak layer, it actually starts to break down the bonds of the snow crystals within that weak layer,” Peitzsch said.
It turns out that newer research in Europe suggests that the onset of wet snow avalanches is happening earlier in the spring. This shift is consistent with broader warming trends and an increase in rain-on-snow events, especially at lower elevations.
“With warmer temperatures, we’re likely to see less snow down low, and potentially more rain on snow events in the future,” Peitzsch said.
However, he also cautions against oversimplifying avalanche risk.
“It’s not as simple as less snow, fewer avalanches,” he said.
This is because conditions vary widely by elevation, region, and snowpack history, making forecasting complex. That’s why Peitzsch emphasizes paying attention to local expertise.
“The first thing to do every day before you head out is to check the advisory from the Utah Avalanche Center,” he said.
To learn more about avalanche research and safety, visit Avalanche.org, the National Weather Service Avalanche Safety site, or check out the Northern Rocky Mountain Science Center's research on Wet Snow Avalanches.
