One more day of cool weather before alpine temperatures soar. Watch for wind slabs on Wednesday and avoid slopes getting hit by the sun.
Confidence
Moderate - Due to the number and quality of field observations
Weather Forecast
WEDNESDAY: Sunny with valley cloud in the morning, light northwest wind, inversion forming with alpine temperatures reaching -4 C.THURSDAY: Sunny with valley cloud, light wind, inversion with freezing level up to 3000 m.FRIDAY: Sunny with valley cloud, light wind, inversion with freezing level up to 2700 m.
Avalanche Summary
Limited reports from the region over the past few days show a pattern of touchy wind slabs around alpine ridges. On Tuesday, a size 1.5 wind slab was triggered by a skier on a south-facing slope at 2600 m in the Invermere area. A Mountain Information Network (MIN) report describes multiple size 1 wind slabs triggered by ski cutting from the Golden area on Sunday. Several size 1 wind slabs were also triggered by explosives near ridge crests throughout the region over the weekend.
Snowpack Summary
Snow from last week's storms is settling and getting redistributed into fresh wind slabs by northwest winds. Roughly 20-40 cm of recent snow sits above various crusts from the warm weather in late November. Two deeper layers may be found in the snowpack, including the November 10 surface hoar and the Halloween crust (80 to 100 cm deep). The late November crust is the most likely of these layers to develop into a problem in the future. Snow depths decrease rapidly below treeline, where the primary hazards are rocks, stumps, and open creeks.
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.