New storm snow is adding to the complexity of the weak and sugary snowpack. Natural avalanche activity is possible and rider triggering is likely. Choosing conservative terrain is recommended.
Recent storm snow may form reactive storm slabs on Thursday. The new snow may be light and fluffy, however, it sits on older and weak snow surfaces that are likely reactive to rider triggering. Natural avalanche activity is a great clue to an unstable snowpack.
On November 29, two natural slab avalanches up to size 2 were reported. A surface hoar layer that sits 15 cm below the surface was the suspect failing layer which then stepped down to the basal facets (weak sugary snow at the base of the snowpack). These reports came in before the recent storm snow arrived and I suspect with the new snow natural and rider-triggered avalanches activity may be seen on Thursday.
We have very few eyes out there. If you do get out riding please consider reporting in the MIN,
Upper Snowpack: 5-25 cm of fresh storm snow combined with strong southwest wind have formed fresh storm slabs at upper elevations. The new snow sits above stiffer, wind-affected snow and in sheltered areas more faceted (sugary, weak) snow which may host a poor bond.
Lower Snowpack: cold temperatures have weakened and faceted the snowpack. A basal rain crust sits near the ground.
Total snowpack depths at treeline elevations are 40-70 cm and in the alpine 60-120 cm. Below treeline elevations remain below the threshold for avalanches.
Wednesday Night5-20 cm of new snow, strong southwest wind and temperatures near -18.
ThursdayCloudy with light snow in the morning, drying with a mix of sun and cloud later in the day. Moderate to strong southwest wind, temperatures steady -15 (ish).
FridayTrace of snow, cloudy, moderate southwest winds picking up overnight Friday. Temperatures gradually warming -12 ish.
SaturdayMix of sun and cloud, moderate West wind and temperatures -8 to -12.
More details can be found in the Mountain Weather Forecast.
