Two longtime local skiers with many years traveling in Snowbasin backcountry were making their second lap of the day into Hells Canyon. Neither of the skiers had avalanche equipment or any avalanche training. They did report being aware of the reported avalanche danger from the UAC. As they were skiing along the ridgeline the first skier took a few turns off the ridge and was heading back to the ridge when the slab broke. The skier behind was also caught on the slab. Brinton immediately got off the slab and stopped on the bed surface. Fred rode the slab a little farther before getting on the bed surface and then eventually stopped when he caught a tree. Fred lost a ski early in the slide. At this time they started heading down the avalanche path to retrieve the lost ski. Due to the steepness and the firm slick bed surface they traversed out to their left to find a different way into the debris pile. They eventually made their way to the debris pile to find a search in progress. After a discussion with rescuers it was determined that no other individuals were involved in the avalanche. All involved parties at this point skied out safely to the parking lot.
Both skiers mentioned having some concern with skiing steeper terrain due to avalanche hazard. Skiing along the ridge they made just a few turns in to the top of the avalanche path intending to just make a few powder turns and then regain the ridge, but that was all it took. They also mentioned that in hindsight they should have ascended back to the ridge and walked down the safer ridgeline to find a safe way to the debris pile.
Reports of an avalanche in the Toilet bowl, it was at first uncertain if any one was involved. Dispatch eventually received a call form people on scene stating that they were on scene and there was one ski in the debris pile. The group on scene performed a beacon search with no find and then began to probe the area. Patrol organized an initial search team of Will King, G.R Fletcher, Jedidiah Getzlaff, and Hans Hjelde with avalanche search dog Pivot. The search team skied to the top of the path. Hans and pivot did a dog search of the area. Will and G.R performed a beacon Search while probing likely burial areas. Jedidiah did the recco search. Probing of dog interest areas going on when the individuals involved skied to the debris pile. It was determined that they triggered the avalanche and no one else was missing.
AS-O-R3D3 average crown size two feet with a max of three feet, east facing 8500’ 130’wide running 800 vertical feet (crown and weak layer estimated from quick descent down avalanche path). Observations of that path five days earlier reported very thin weak faceted snow. The path in question has slid numerous times throughout the season. This avalanche failed on facets near the ground. A recent storm of 19” with 1.43 H2O put a new load on a structurally weak snowpack. The avalanche released with the weight of two skiers.
Forecaster Comments -Thanks to GR Fletcher of Snowsafety for the excellent write-up