Significant warming is expected to increase the reactivity of weak layers and cornices.
Verify conditions as you travel and back off if you notice signs of instability.
Cornices will be a significant concern on Saturday, with warm tempertures and sun in the forecast. Avoid travelling on or under large cornices, especially during the warmest parts of the day.
Storm slabs may become more reactive with the foreacst warming; especially on sunny slopes, in wind-loaded areas or where they overlie a weak surface hoar layer.
Several size 1 to 2 storm slab avalanches were reported in the Lizard Range over the past three days. Some were naturally triggered, and a few were caused by explosive control. They generally occurred in the alpine on wind-loaded northerly through easterly slopes.
A large natural cornice fall was also observed on Thursday.
Looking forward, we expect to see increased reactivity with storm slabs and cornices during the warmest parts of the day.
Storm snow accumulated over the past few days, combined with strong southwesterly winds, has created storm slabs across all aspects and elevations. Wind loading has built up large cornices and formed deeper, more reactive slabs on leeward aspects, especially near ridgetops.
A weak layer of surface hoar can be found in some sheltered terrain features buried 40 to 60 cm under the recent storm snow. In other areas, a melt-freeze crust can be found at similar burial depths up to around 2000 m. These layers will be tested by the warming this weekend, and could become reactive as temperatures rise.
The mid and lower snowpack currently has no layers of concern.
Friday Night
Cloudy. 35 km/h west ridgetop wind. Treeline temperature -4°C. Temperature inversion developing, freezing level approximately 1400 m.
Saturday
Mix of sun and clouds. 40 km/h west ridgetop wind. Treeline temperature 0 °C. Temperature inversion in AM. Freezing level rising to 1900 m.
Sunday
Cloudy. 1 to 5 cm of snow. 40 km/h west ridgetop wind. Treeline temperature -3 °C. Freezing level rising to 1600 m.
Monday
Mostly cloudy. 2 to 10 cm of snow. 50 km/h southwest ridgetop wind. Treeline temperature -1 °C. Freezing level approximately 1900 m.
More details can be found in the Mountain Weather Forecast.
