Quick report
- Red Flags
- Recent Avalanches, Heavy Snowfall, Wind Loading, Cracking, Poor Snowpack Structure
- Red Flags Comment
- <p>Poor snowpack structure that saw activity today was due to the supportable bedsurface from Wednesdays snow and warm temperatures. Slope cuts were easily triggering long running Loose Snow Dry Avalanches in the light density new snow that fell since 2200 on Wedensday. One such long running sluff ran at least 650 vertical on a NE facing gully off of Claytons. The associated weak layer was the previously mentioned graupel, and these graupel pellets were very large and up to 4 mm in size. In many areas the graupel layer was 6 cm deep. As the day progressed the sensitivity of this weakness became less reactive, yet even at 1400 it was still easy to slope cut this weakness on slopes with angles > 35 degrees. </p> <p>In areas receiving even minimal wind transport and loading insignificant cracking was observed, but it would not be unlikely that in the most exposed and loaded terrain in the upper elevations these issues were greater and more problematic. </p>
Snowpack
- Instability Comment
- <p>See above, unfortunately no photo of the one off of Claytons due to poor visibility. This Slide was approximately 45 feet wide and kept entraining significant amounts of snow upon descent. Regardless, this problem was manageable. </p> <p>It is likely that this problem will continue decrease in danger trend wise due to the residual warmth of the snowpack and it's associated venting. </p> <p>There was also several areas where there were small naturals of Loose Dry that appeared to run during the high PI rates. </p> <p>See above with regard to cross loading potential that may have helped make the slide on the west face of Milly more cohesive. Lingering wind slabs on Friday may still be of concern in the upper elevation exposed and loaded terrain. These slabs may become less sensitive as Fridays temperatures begin to skyrocket. </p>
Storm totals never seemed to be able to get more than 12 inches despite continued snowfall throughout the day. The residual warmth venting out of the snowpack kept grabbing the new snow and assimilating it into the buried wet and damp underlying layers. Wednesdays storm appeared to drop 4 to 5 inches with the upper half of this being graupel. At 0900 there was only 3 inches of light density snow that fell overnight, yet due to the heavy snowfall rates at least another 7 fell during the day. Also in the early morning hours the "scratchy old snow/frozen surface made for slippery riding. Fortunately conditions improved as the day progressed along with accumulating snow.
Soft wind slabs were forming in the upper elevation exposed terrain in the Back Bowls. The slide off of the West face of Milly appeared to have gained cohesiveness due to cross loading. In other areas there were 4 finger plus wind slabs, and associated scouring in the fetch areas.