The avalanche danger is high throughout much of Utah, including the Wasatch Range and Uinta Mountains.
Utah Avalanche Center Forecaster Greg Gagne said recent storms have made the snowpack unstable.
“The Utah Avalanche Center has issued an avalanche warning, pretty much statewide,” Gagne said. “So this means that we have dangerous avalanche conditions and we are advising people not to enter avalanche terrain: That is, slopes approaching 30 degrees or steeper.”
Yesterday’s snowfall didn’t reach the levels many were hoping for or predicting. But Gagne said the 8-12 inches that fell in the mountains near Park City and Salt Lake City, and the type of snow it was, changed conditions on the ground.
“Those aren't huge snow totals, but it's the water amount,” he said. “So, the snow that's fallen has been heavy and dense, so we've added a lot of water weight. Over an inch of water. So that's really what we're paying attention to, and combined with these strong winds, they've created dangerous avalanche conditions.”
The conditions were already unstable. Snowstorms this fall created what’s known as a persistent weak layer at the base of the snowpack. Slopes that are completely in the sun — generally those that face south — saw all of that early-season snow melt, allowing the December storms to fall on bare ground.
But on shaded slopes that face the northern half of the compass, that early-season snow stayed and rotted in place, losing its moisture and ability to bond with the snow above it. That weak layer is now holding up all of the snow that’s fallen in recent weeks.
“We've had this persistent weak layer — we've been talking about it now for a couple of weeks. Every time we’ve put a new load of snowfall or wind-driven snow, we've seen reactivity, we've seen avalanching,” Gagne said Friday morning. “And we quickly overloaded this weak layer overnight, so I'm expecting natural avalanches and human-triggered avalanches to be likely on this weak layer. Again, mid- and upper-elevation slopes facing west through north and east.”
With snow predicted for the foreseeable future, Gagne advised caution.
“My advice simply is just don't travel in that terrain right now. It's just too dangerous, and we have a lot more snow and wind on the way,” he said. “… We expect the avalanche danger to remain high for the next several days, so be patient out there folks.”
For the latest avalanche information, including forecasts, observed avalanches and week-in-review reports that offer a broader perspective, visit utahavalanchecenter.org.
