Ed LaChapelle and Monty Atwater worked in Little Cottonwood Canyon in the 1950's. Atwater put together Ten Contributory Factors for avalanche hazard evaluation in 1954. Check out his typewritten notes on direct action slab avalanches that are still relevant to today's avalanche problems. For further reading on contributory factors from Ron Perla there is a more in depth article from 1970 HERE.

We're in for a run of large storms that began on Tuesday December 27, 2022 set to impact the state throughout the next week. See Trent and Mike's weather discussion HERE. The buried persistent weak layer (PWL) has plagued us since it formed during high pressure in November. It was subsequently buried at the end of November and we saw low elevation avalanches on this persistent weak layer at elevations below 8000' including a few close calls with people getting run through forested avalanche terrain. Since the first avalanche cycle ran it's course in mid December this PWL has been …

Our Week in Review highlights significant snowfall, weather, and avalanche events of the prior week. (Review the archived forecasts for the Salt Lake mountains.) The danger roses for the Salt Lake mountains from Friday, December 16 through Thursday, December 22: Summary: Friday, December 16: The UAC issues a Special Avalanche Bulletin emphasizing the heightened danger of large avalanches occurring on northerly aspects where there is a buried persistent weak layer (PWL). The danger is pronounced at low and mid-elevations. Clearing skies and cold …

Dangerous and Unusual Avalanche Conditions Across the State Three significant avalanche accidents have occurred in the past week. Two accidents required the assistance of Search and Rescue to evacuate the injured victims. Another victim was unconscious but soon able to self-evacuate. WHAT IS UNUSUAL is that each of these avalanche accidents took place in the lower elevations bands below 8000’. What this means is that these avalanches can occur not far from parking lots or trailheads. These dangerous avalanches are 1-4’ deep at the top fracture line and easily triggered from …

The danger was “only” moderate that day. My friends and I had climbed up through south facing terrain looking to ski powder in an upper alpine north facing bowl. It was a beautiful day. The danger had recently dropped, and we didn’t see or experience any outward signs of instability such as cracking, collapsing, or recent avalanches. When we reached the top of the ridge and peered into the bowl on the other side, we saw numerous sets of tracks. We quickly transitioned, dropped in one at time, and shredded the fresh powder without incident. Wanting more and feeling good about …

Our Week in Review highlights significant snowfall, weather, and avalanche events of the prior week. (Review the archived forecasts for the Salt Lake mountains.) The danger roses for the Salt Lake mountains from Friday, December 9 through Thursday, December 15: Summary: A long-duration storm that begins on Sunday evening and lasts through the week with 2.5' - 6' of snowfall in the Cottonwoods containing 1.5" - 2.75" of snow water equivalent (SWE) and 1.5' - 3' of snowfall in the Park City mountains (containing 1" - 1.5" SWE). Numerous natural and human-triggered …