The holy trinity of low hazard, no wind and good riding everywhere is gone. Thin wind slabs are lurking around in the alpine - watch the big fans under head walls and moraine features. Terrain unmolested by the wind should still be good riding . [PJ]
Confidence
High - Due to the number of field observations
Weather Forecast
Some light snow (5mm) forecast for Monday. Winds will be light and variable in the alpine. Freezing levels will be in the valley bottom for the next 3-4 days.
Avalanche Summary
A small avalanche cycle, up to size 1.5 was observed today along the Smith Dorrian/Spray HWY as a result of the winds yesterday and through the evening. These were predominantly thin, 10-20 cm wind slabs and most of them were on north, northeast and east aspects directly below large alpine head walls. These small slab avalanches were observed between 2400-2600 meters. Some cross-loading did occur as well but no natural avalanches were produced from the influence of the winds on these features.
Snowpack Summary
The winds have finally come back to K-Country. 5-10cm hard slabs have formed in exposed alpine features overnight. The snowpack from TL and below is losing its strength and structure due to faceting from cold temps. Below 1900 meters, the snowpack is rotten to the ground and exhibiting more normal characteristics. Above 1900 meters the snowpack is supportive but the upper snowpack is also losing strength. Cornices continue to develop.
Problems
Wind Slabs
Wind Slab avalanches are the release of a cohesive layer of snow (a slab) formed by the wind. Wind typically transports snow from the upwind sides of terrain features and deposits snow on the downwind side. Wind slabs are often smooth and rounded and sometimes sound hollow, and can range from soft to hard. Wind slabs that form over a persistent weak layer (surface hoar, depth hoar, or near-surface facets) may be termed Persistent Slabs or may develop into Persistent Slabs.