New snow overlies a prominent weak layer in sheltered areas at treeline and below. Avoid areas where snow feels stiff or slabby.
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With plenty of snow available for transport watch for localized winds building fresh reactive wind slabs in lee terrain features. Windslab are most reactive during formation.
A weak layer of surface hoar and facets or a crust exists 30 to 60 cm down. This layer is reactive to human-triggering where a slab has developed above it. Watch for signs of instability: whumphing, shooting cracks and recent avalanches.
On Monday, a few human-triggered size 1 wind slab avalanches were reported in northerly alpine and treeline features. Avalanche control produced several explosive-triggered persistent slab and dry loose avalanches, up to size 1.5.
A size 2 natural wind slab avalanche was observed in northeast-facing alpine terrain.
We expect unconsolidated snow will remain reactive to skier traffic on Wednesday in steep terrain. Carefully manage sluffing in steep terrain.
Storm snow totals range from 30 to 50 cm, with deeper deposits in wind-loaded areas. The new snow is bonding poorly to old surfaces, which include melt-freeze crusts on sun-exposed slopes, surface hoar or facets on shaded slopes, and wind-affected snow at higher elevations.
A weak layer of surface hoar of facets is buried, 30 to 60 cm deep. Where this layer is preserved it may be reactive to human triggering.
A weak layer of facets from early December is buried 60 to 120 cm deep.
The base of the snowpack consists of a thick crust with facets or depth hoar in many areas.
Tuesday Night
Partly cloudy with a chance of flurries, 0 to 1 cm of snow. 10 to 15 km/h variable ridgetop wind. Treeline temperature -20 °C.
Wednesday
A mix of sun and cloud. 10 to 25 km/h west ridgetop wind. Treeline temperature -16 °C.
Thursday
Mainly sunny. 10 to 15 km/h northwest ridgetop wind. Treeline temperature -15 °C.
Friday
Mainly sunny. 5 to 15 km/h northwest ridgetop wind. Treeline temperature -15 °C.
More details can be found in the Mountain Weather Forecast.
