Quick report
- Red Flags
- Wind Loading, Collapsing, Poor Snowpack Structure
- Red Flags Comment
- <p>Same tour as yesterday, but more red flags today. Just goes to show how quickly things change. When we reached the base of corkscrew we noticed our tracks from yesterday were completely filled in. This was in the biggest shot just lookers left of center. As we crossed below this slope the snow beneath our skis was dense and slabby. Wind loading definitely occurred overnight in this zone. On our second lap I felt a large collapse along with an audible whumpf when Casey dropped in to an open shot approaching 30 degrees in steepness. The weak layer we identified yesterday failed on this slope, and I felt the snow beneath my skis drop. No cracks in the snow associated with this collapse. Poor snowpack structure remains in this area, see yesterday's observation for more details on that. Today there was more of a slab in place and we were a bit more careful with our terrain choices. </p>
In the first photo you can see snow plumes blowing off the summit of Tuk No. The second photo is the meadow where I felt a large collapse. It happened on Casey's second turn after dropping in.
Snowpack
- Instability Comment
- <p>The persistent weak layer remains on N and NW aspects in the low and mid elevation bands. You'll find this layer of facets about 33cm below the surface. Yesterday this layer was reactive to compression tests, but did not propagate on an ECT. We felt good about skiing because we didn't have much of a slab in place. We said if there was more of a slab, wind slab or otherwise, we would be uncomfortable skiing on top of this weak layer. The original plan today was to ski the shots on the skiers right which are a little steeper and more northerly than what we skied yesterday. The plan was quickly changed when we saw the wind loading that occurred overnight. The snow in the upper part of the pack varied a lot today, and was definitely more slabby than yesterday. We worked the terrain on the far skiers left which is more westerly and lower angle. We still had a collapse on this weak layer in a NW (305 degrees) facing meadow around 10,000 ft. </p> <p>Today we observed plumes blowing off the summit of Tuk No. and loading it's west facing slopes. Easterly winds on the upper elevation ridges were light to moderate. A significant amount of loading also occurred overnight on NW facing slopes in the corkscrew glades. Enough wind loading happened that there is a real possibility of human triggered avalanches in these fresh drifts on top of the buried PWL. </p>
A trace of new snow was all we found today.