After a large avalanche was triggered in Big Cottonwood Canyon on Monday, the Utah Avalanche Center is encouraging all backcountry travelers to avoid west, north, and east facing terrain – particularly if it is steeper than 30 degrees.
Monday’s avalanche occurred in the Mineral Fork area of Big Cottonwood Canyon after a group of experienced skiers dropped into the Barrieto slope to make what’s called a slope cut. As one skier was traversing, a large slide was triggered that was 2-4 feet deep and 600 feet wide. The avalanche ran 1,600 vertical feet to the bottom of the slope and had enough momentum to travel partway up the opposite side of the drainage.
Thankfully, none of the skiers were caught in the slide and all are ok.
Avalanche forecaster Trent Meisenheimer said avalanches are likely to occur throughout Utah this week.
“Many large and dangerous human-triggered avalanches have occurred over the past several days," he said. "Basically the state of Utah right now has this same issue where we have weak, faceted snow that’s now buried and avalanches are now failing 2-4 feet deep and well over 100 feet wide and can easily catch, carry, bury, and kill a human.”
Utah’s current weak layer of snow is what’s left from December’s snowfall. That snow had been consistently exposed to the elements throughout the state’s unusually dry January and February and created what’s called a persistent weak layer after getting covered up by recent snowstorms.
A persistent weak layer of snow is formed when old snow begins to melt and refreeze to form large crystals that don’t attach to other snow layers. These layers are very unstable and can easily trigger avalanches if they are loaded with enough weight to make them collapse.
Meisenheimer said he will personally avoid being on or below any slope steeper than 30 degrees. He said shady slopes in the west, north, and east directions are particularly dangerous right now.
“Basically, I have zero confidence in our snowpack right now, and there’s really no secrets," Meisenheimer said. "It’s not like avalanche professionals are out there navigating through terrain. Basically, people with years of experience and avalanche professionals, we’re just avoiding this type of terrain all together.”
The most current avalanche conditions can be found here.