Quick report
- Red Flags
- Wind Loading, Cracking
- Red Flags Comment
- <p>Wind was clearly a factor, with cornicing along the summit ridge and wind rippling above 8000' visible from the parking lot. Wind continued to transport snow throughout the day at low- and mid-elevations (and presumably at upper-elevations as well, though we didn't venture that high). We triggered 4 avalanches throughout the day, all relatively small, including an intentional trigger with a sympathetic release, an unintentional trigger while skinning, and a remote trigger while skiing. See the avalanche obs for more details on those. We also noted cracking on wind-loaded slopes throughout the day. </p>
Snowpack
- Instability Comment
- <p>Lots of wind loading happening, with some slabs up to 60cm thick and 4F hardness atop the F hardness storm snow. Given the sustained winds today and the possibility for a bit more snow, I anticipate this problem will continue or worsen through the evening and into tomorrow (12/28). I imagine what sheltered terrain still exists will ride quite nicely tomorrow, but anything wind-affected will be worth avoiding on angles >30 degrees or on convexities. Today's tour certainly met the requirements for a Considerable hazard; depending on wind effects and additional snow overnight, I wouldn't be surprised to see naturals tomorrow and a High hazard.</p>
We passed two parties exiting on our way up the skin track, both of whom reported a wind slab avalanche on an easterly 25 degree slope in the area of Dead Tree (approx. 8000'). Given this information and the increasing wind, we poked around in the snow at the LZ (approx. 6600') and found about 30 to 60cm of storm snow (F) atop a thick ice crust (the rain leading the Christmas storm), a layer of 4F snow, and additionally ice crust near the ground (the rain from the storm preceding the Christmas storm). A quick ECT was unreactive. Informal shovel shear tests indicated an interface in the storm snow about halfway down, depending on precise depth of new snow at that spot, as well as easy sliding of the storm snow on the existing ice crust.
We hunted for potential buried surface hoar given the pre-storm obs and found inconsistent evidence of them near the base of the storm snow. We did not see any significant facet growth adjacent to the ice crusts.