Watch for wind slabs in exposed terrain features at higher elevations. Although a cool day is forecasted, assess snowpack warming on southerly aspects from the sun. Also watch your overhead exposure, as cornice falls could trigger slab avalanches.
Weather Forecast
SATURDAY: Sunny, light westerly winds, alpine temperature -10 C, freezing level rising to 1000 m.SUNDAY: Mostly cloudy with light afternoon snowfall, accumulation 2 to 5 cm, light southwesterly winds, alpine temperature -6 C, freezing level 1000 m.MONDAY: Cloudy with morning snowfall, accumulation 10 cm, light northeasterly winds, alpine temperature -12 C, freezing level 700 m.
Avalanche Summary
On Thursday, a few loose dry avalanches occurred in steep and rocky alpine terrain on sun-exposed aspects.On Wednesday, large (size 2 to 3) wind slabs were observed in the region, being triggered naturally and by explosive control. They were generally on easterly aspects, 20 to 30 cm deep, and at treeline and alpine elevations.Cornices have also been reactive this week, with numerous releases from natural and explosive triggers.
Snowpack Summary
Around 5 to 10 cm of snow fell on Friday. Wind slabs may linger on all aspects at higher elevations, produced from the redistribution of last weekend’s storm snow with variable wind directions. This snow sits on a melt-freeze crust on sunny aspects and all aspects below 1600 m, as well as surface hoar on north aspects above 1600 m. At ridgetop, cornices are large and have been failing in the past few days. At low elevations, expect to find a surface crust or moist snow on southerly aspects.Deeper in the snowpack, the late-November weak layer is composed of weak and sugary facets around a crust, which is buried around 200 to 300 cm and considered dormant.
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.