There is uncertainty on how prolonged warming will impact an already wet and weak snowpack.
Stick to simple, non-avalanche terrain and avoid exposure to overhead hazard.
A weak layer of surface hoar is buried around 30 to 60 cm deep. Additional snow load and warming will increase the likelihood of triggering, as well as the size of avalanches running on this layer.
Recent snow accompanied by moderate to strong southwest winds has built reactive storm slabs. These slabs may step down to deeper persistent layers, triggering larger than expected avalanches.
A crust with weak facets and/or depth hoar exists at the base of the snowpack. This layer is most likely to be triggered in thin snowpack areas. Prolonged warming will increase the likelihood of natural activity.
On Monday, several natural and human-triggered storm slabs (size 1-2) were observed on a variety of aspects and elevations. Observations were limited by stormy weather.
Preliminary reports on Tuesday indicate that a natural avalanche cycle occurred as freezing levels rose to near mountain top.
Looking forward to Wednesday, warm temperatures and sun will continue to destabilize an already weak snowpack.
Rain and warm temperatures have created a wet snow surface to at least 2200 m. A weak crust may form on the surface from clear skies overnight. At upper elevations, up to 25 cm of recent storm snow has been redistributed by strong southwest winds.
Around 40 to 60 cm of snow overlies a persistent weak layer of surface hoar in wind-sheltered terrain, and a sun crust on steep south-facing slopes. New storm snow and warm temperatures may overload these layers, creating large avalanches.
A deep persistent weak layer consisting of a thick melt-freeze crust, with weak faceted snow and/or depth hoar, can be found near the ground in shallow snowpack areas.
Tuesday Night
Partly cloudy. 30 km/h west ridgetop wind. Treeline temperature 1 °C. Freezing level 3200 m.
Wednesday
Sunny. 50 km/h west ridgetop wind. Treeline temperature 0 °C. Freezing level 3200 m.
Thursday
Sunny. 40 km/h northwest ridgetop wind. Treeline temperature -2 °C. Freezing level 1200 m.
Friday
Sunny. 20 km/h northwest ridgetop wind. Treeline temperature -4 °C. Freezing level 300 m.
More details can be found in the Mountain Weather Forecast.
