Mt. Reba Loose Wet Avalanche

My party triggered a wet loose slide on reba at approx 1430 on 3/23.  My estimates the toe of the debris was 100m wide and the slide was R1D2As path length 800 ft

 

We (skier 1 - myself, and skiers 2, 3 and 4) left the snowpark on 207 at 1200 and headed up toward the round valley ridge, skied a short north facing pitch into the upper valley, finding boot top to knee deep good skiing. The visibility was improving and we headed up the lower angle slope at the head of valley to the reba ridge. Temperatures were warming down low and there was a softer crust present under the recent snow on the S/SE with some visible wind drifting out of the S and SW. We got to the top around 2 and waited to determine if visibility would persist to ski the main slope. Surface conditions at the top were firm but edgeable crust with 2-4 in of soft wet snow. When we stopped to develop a plan for skiing the main pitch with our party of four we noticed a wind drift of snow deeper than boot top on the skiers left side and sign of scouring on the skiers right of the path. Our plan was to ski the central/right side of the path and ski out to the bottom flats instead of pitching out the run to reassess and keep the group together. Skier 1 and 2 had radios. Skier 1 left the group aiming the ski the central fall line, finding a few inches of wet snow but not breaking down to the crust. About 2/3 the way down the run skier 2 made a radio call that caused skier 1 to glance uphill and see 2-3 ft of flowing snow moving 20-30mph. Skier 1 was able to traverse out of the path with the slide at their heels. After regaining radio and visual contact it was decided that if visibility was lost skier 2,3 and 4 would ski out out "B" route on the lower angle southeast aspect. That was what end up happening. We were unable to get pictures on saturday and returned sunday morning when the clouds cleared. Upon inspection of the lower end of the path on sunday morning the widespread ice crust was much firmer down in the path than up higher, with about 5 inches of snow on top. 

 

In hindsight it is easier to see that multiple red flags, warming, wind, new snow were not taken seriously enough. After skiing out of the path, skier one saw two other natural wet loose slides breaking from under the rock bands at mid elevations that were not seen based on the aspect of approach. At the end of the day we got  lucky, the consequence of getting caught in this slide was a risk we determined was unacceptable. In the picture it maybe hard to see, but the debris is  5' +deep in places. 

 

When debriefing the incident it was clear if that if slope was to be skied the group should have moved slower and kept together while assessing the changing snow conditions as we dropped elevations. We had discussed multiple other routes that would have held similar quality skiing without exposing our selves to similar hazard. 

We were incredibly thankful to have radios given the incident, but wonder if they gave us a false sense of being able to effectively communicate what we were seeing out there to each other and a greater willingness to spread out more as a group.