Slab avalanches may be primed for human triggers. Choose conservative terrain and back off slopes when you see signs of instability such as cracking, whumphing a fresh avalanche activity.
40-60 cm of snow currently sits above a buried crust from early December. Sugary, facets above and/or below the crust may weaken the bond and the persistent slab may become reactive, especially to human triggers.
The new storm snow is building reactive storm slabs. Strong southwest wind is forming deeper slabs on leeward slopes that could produce larger avalanches. Loose-dry sluffing will likely occur from steep terrain features.
Friday: Snow amounts 5 cm with alpine temperatures near -5. Ridgetop wind strong from the southwest and freezing levels valley bottom.
Saturday: Snow 5-10 cm with alpine temperatures near -7. Strong wind from the West and freezing levels 900 m.
Sunday: Snow amounts 10-20 cm. Alpine temperatures -1 and freezing levels 2000 m. Ridgetop wind 20-85Km/hr wind from the southwest.
On Thursday, a natural size 2 storm slab from NE alpine terrain was reported. As per the report, this slab likely failed on Wednesday. On Thursday, explosives were able to trigger slabs up to size 2 in the alpine and a size 1.5 at treeline.
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Strong wind from the southwest and up to 30 cm of new snow will likely build reactive storm slabs. The recent storm snow accumulations bring 40-60 cm above the early December crust which may have persistent weak, and facetted crystals above and below it. With slab cohesion adding stress and load on that interface, we may see this persistent slab avalanche problem come to life.
Deeper in the snowpack are two hard melt-freeze crusts that formed in November. The concern would be if there were weak faceted grains around the crust, but there is uncertainty if and where in the region this may be a problem. Without any recent avalanche activity, it appears that this layer is dormant for the time being.
