With limited field observations, forecasters have uncertainty about how storm snow is bonding to old surfaces at higher elevations. Approach this time of uncertainty with skepticism and asses conditions as you travel through the terrain. If you see signs of instability, natural avalanches, whumpfing, and shooting cracks, consider a higher danger rating.
Moderate to light southerly winds have redistributed 30-50 cm of new snow into deep pockets at higher elevations. Where snow remained dry expect to find pockets of storm slabs that are reactive to human-triggering. Be especially cautious transitioning into wind-loaded terrain, more reactive deposits lurk in leeward features.
On Tuesday, a size 1.5 wet slab avalanche was reported at 1450 m.
On Monday, natural wet slab avalanches, up to size 2.5, were observed at 1800 m and below. Slab depths were 40-60 cm.
On Sunday, a size 2.5 natural storm slab avalanche was observed on an east aspect in the alpine.
Please continue to post your observations and photos to the Mountain Information Network.
Since December 30-50 cm of storm snow has accumulated in the alpine. Variable southerly winds have built cohesive slabs in lees. We suspect a thin rain crust exists down 20 within the storm snow. Below 1600 m the snowpack shrank from the heavy rainfall and is now refrozen and very firm.
At higher elevations storm snow covered a layer of facetted and unconsolidated snow that formed during the mid-December cold weather. Snowpack depths reach 140-180 cm at treeline and higher.
Wednesday Night
Isolated flurries, trace accumulation. Southwesterly wind 20 km/h gusting 30 km/h. Ridgetop low temperature -6 C. Freezing levels 300-500 m.
Thursday
Mostly cloudy with isolated flurries, trace accumulation. Southerly wind 20 km/h gusting 40 km/h. Ridgetop high temperature -1 C. Freezing levels rise from 500m to 1000 m by the end of the day.
FridayCloudy with isolated flurries, 5-10 mm. Southerly wind 40 km/h. Ridgetop high temperature -1 C. Freezing levels hover from 700 m to 1000 m.
SaturdayMostly cloudy with isolated flurries, 2-5 mm. 20-40 km/h southwesterly wind. Ridgetop high temperature -1 C. Freezing levels hover near 1000 m.
More details can be found in the Mountain Weather Forecast.
