Brilliant clear days ahead! The sun is getting higher in the sky at this time of year and can pack a punch. Keep an eye on solar exposed slopes and be ready to back off if they start to show signs of instability like pinwheeling.
This problem will likely be focused in wind loaded lees of exposed terrain features. Fresh snow is likely to shed easily from steep slopes that see sun.
Natural cornice falls have been reported recently and will likely continue as the sun comes out over the next few days. Cornice falls are dangerous in their own right but they may also trigger avalanches on slopes they impact.
Tuesday night: Clear. Light northwest wind. Alpine low -16 C. Freezing level valley bottom.
Wednesday: Sunny. Light northwest winds. Alpine high -5 C. Freezing level 1000 m.
Thursday: Sunny. Light southwest wind increasing to strong at ridgetop. Alpine high -3 C. Freezing level 1300 m.
Friday: Sunny. Moderate southwest wind, strong at ridgetop. Alpine high -3 C. Freezing level 1400 m.
Observed Monday; natural and explosive triggered cornice falls size 1.5-2, occasionally triggering thin slabs on slopes below.
There have been two reports of avalanches running on the early February rain crust. Explosive control work produced a size 2 with crown depth up to 80 cm on Tuesday. A skier triggered size 2 on a southeast aspect is described in this MIN report from Sunday.
A thin sun crust may be found at the surface on steep solar aspects. Recent snow has been wind loaded into thick, slabs in immediate lees of ridge crests at alpine and exposed treeline elevations. In sheltered areas, the recent snow is settling and may contain various sun crusts and layers of small surface hoar crystals.
A thick rain crust sits 30-60 cm below the surface, up to 2100 m. A slab/weak layer/slick bed surface configuration may be imminent as faceting has been observed between this crust and overlying snow.
The bottom 20 cm of the snowpack consists of basal facets and decomposing crusts that have not been an active avalanche problem since December, but could reemerge as a problem after sustained warming.
