Quick report
- Red Flags
- Recent Avalanches, Wind Loading, Poor Snowpack Structure
- Red Flags Comment
- <p>Poor snowpack structure appears to be becoming more reactive each day with the upper layers of the snowpack becoming more dense, consolidated and slab like. Numerous avalanches reported on the 27th appear to help identify the distribution of the propensity for propagation in the Persistent Slab Problem that exists in lower and mid elevations in the outlier areas outside of the Cottonwoods. Of note: Snow Pit in West Willow, ENE at 9450 feet indicated that this issue is present in this location. CTM Q2 scores and an ECTP24 SC, down 70 cm, that had a distintive "zipper sound" reflects the same buried weak layer issues seen in other similar locales. Weak layer was small NSF's (.5 mm in size). Also of note was the large avalanche that appeared to Natural sometime around late Monday during the High PI, and W to SW wind event. Crown was at least a meter deep and 700 feet wide in its main segment with another 400 feet in adjacent unconnected paths on each flank. Slide was in the "Arm Pit" of West Willow. Another small pocket 70 feet wide released at a similar depth further down the West Willow ridge to the east. The main slide in the Arm Pit ran to the flats and appeared to pile up significant debris that has since been buried. There was 7 to 9 inches of new snow on the bed surface, and the bed surface was a mostly supportable M/F crust that formed prior the beginning of the storm two Wednesdays ago. The frigid temperatures in combination with the remaining bed surface crust appear to be working together to help in accelerating facet development in the new snow on top of this slide path. </p>
Snowpack
- Instability Comment
- <p>See above, as well as the numerous Persistent Slabs Avalanches reported. The cold temperatures appear to helping stiffen the settling of the new snow and make the slab more cohesive and consolidated; and this appears to be aiding in the increasing trend of this Persistent Slab Problem/issue. </p> <p>Danger in area traveled today was Moderate, yet with the Natural activity and remote triggering reported, Considerable appears to be the appropriate Danger. And, with the widespread nature of this Persistent Slab issue at lower and mid elevations Considerable Danger appears to be happening on Saturday even if the Winds die down and quit loading. </p> <p>Reports of Strong winds on the exposed ridges with Moderate loading have increased Wind Slab avalanche potential. Plumes and active loading was observed on almost all upper elevation ridgelines. </p>
Excellent riding on settled powder that appears to get denser each day despite the upper 10 cm that remains loose and beginning to facet. Exposed ridges on the Westerly aspects had wind sculpting and sastrugi, Daytime heating and direct sun began to dampen the SE aspects first and this damage continued around the compass to SW by mid afternoon. Subsequent M/F crusts ensued.