Large persistent slab avalanches may remain possible to human trigger on steep slopes at treeline and above.
Avoid steep or convex slopes where triggering slabs is more likely.
A weak layer of facets and/or surface hoar is buried 50 to 100 cm deep. It is most prominent on terrain features sheltered from the wind. Where this layer exists, it remains possible for the weight of a person or machine to trigger it.
Naturally triggered wet loose avalanches may occur in steep terrain during the heat of the day. Cornices also weaken and could release naturally. These could step-down to deeper layers, resulting in large avalanches.
Several naturally triggered wet loose avalanches up to size 1.5 were reported on sunny aspects on Thursday.
Dry, settled snow is found on shaded aspects in the alpine. A hard melt-freeze crust exists on the snow surface on sun-exposed slopes to the mountain tops and on all aspects below treeline. The crust will transition to wet snow with daytime warming and re-freeze at night.
50 to 100 cm of snow overlies a hard melt-freeze crust from early April. The overlying snow is slow to bond to the crust where pockets of weak surface hoar or faceted grains rest on the crust, which is most likely on northerly aspects at treeline and alpine elevations.
Friday night
Clear skies. 20 to 30 km/h southeast ridgetop wind. Treeline temperature around -3 °C. Freezing level 500 m.
Saturday
Sunny. 20 to 30 km/h southeast ridgetop wind. Treeline temperature +2 °C. Freezing level 1700 m.
Sunday
Mix of sun and cloud. 10 to 20 km/h west ridgetop wind. Treeline temperature +1 °C. Freezing level 1500 m.
Monday
Mix of sun and cloud. 10 to 20 km/h southwest ridgetop wind. Treeline temperature +1 °C. Freezing level 1500 m.
Check out the Mountain Weather Forecast for additional weather information.
More details can be found in the Mountain Weather Forecast.
