Accident: Little Cottonwood Canyon

Observer Name
UAC Staff
Observation Date
Thursday, March 16, 2023
Avalanche Date
Wednesday, March 15, 2023
Salt Lake » Little Cottonwood Canyon
Location Name or Route
Little Cottonwood Canyon Neighborhood
Slope Angle
Avalanche Type
Roof Avalanche
Avalanche Problem
New Snow
Buried - Fully
Accident and Rescue Summary
On the afternoon of March 16, 2023 a group of children was playing next to a roof-line in a neighborhood in Alta. At approximately 5:20 PM snow avalanched off the roof and buried one of the children. Another child witnessed the slide and knew their peer was buried. 911 was contacted and nearby adults starrted to spot probe the debris in the last seen location. 911 dispatchers contacted Alta Central, and they dispatched an Alta Marshall, Unified Fire Station 113, and Life Flight. UDOT employees on their way home overheard the radio call and responded to the location to assist. The area was marked off as a known roof slide location.
Rescuers were able to spot probe in the debris based on witness's last seen location and had a positive probe strike. The victim was buried approximately 1.5-2' under the snow, face down. They were buried for 5-10 minutes. They regained consciousness and were talking to first responders prior to being loaded into the air ambulance.
Thank you to everyone who responded; without quick action and availability this story may have had a different ending. Thank you to all the organizations that responded (nearby neighbors, plow drivers, caretakers, Alta Central, Alta Marshall's Office, Unified Fire, Life Flight Air Ambulance, UDOT forecasters)
Weather Conditions and History
Alta, Utah is at record snowfall for the 2022-23 winter season. So far in the month of March the Collins Study Plot located at 9662' reported 100" of snow and 8.38" of water. Prior to this roof slide the Collins Study Plot reported a storm with 16.5" of snow and 2.21" of water. The storm was high density graupel snow with southerly winds gusting to the strong range with very little to no sun.
The forecast for the Salt Lake Area mountains which includes Alta, UT the day of March 15, 2023 was rated at a CONSIDERABLE avalanche danger. The UAC had a report of a roof avalanche on March 14, 2023 in a nearby neighborhood in upper Little Cottonwood Canyon. The March 15 forecast stated "Between warm temperatures, overnight rainfall, and so much snow on rooftops in mountain communities, roof avalanches could be a significant hazard today."