Spring conditions. Localised storm slabs may develop this weekend.
Weather Forecast
A cold front arriving overnight and lingering on Sunday brings 10-20 cm snow, with moderate SW winds. The freezing level should fall to around 1100 m by Sunday morning. A mix of sun and cloud, light winds and cool temperatures are expected on Monday and Tuesday.
Avalanche Summary
No recent avalanches have been reported. A few large wet slab avalanches were observed 5-7 days ago. At least one of these failed on a melt-freeze crust down about 30 cm. Most operators have shut down for the season. Please continue to share your backcountry observations through the Mountain Information Network.
Snowpack Summary
As temperatures gradually cool through the weekend, loose wet and wet slab avalanches will become less likely. Storm slabs may develop in the alpine as the cold front passes through. At lower elevations, monitor the overnight freeze of the snow surface. If the snow surface does not freeze overnight or if the crust is thin or breakable, daytime heating or rain will weaken the snowpack much more quickly than if there is a well frozen thick crust. Low elevation and thin snowpack areas are isothermal.
Problems
Storm Slabs
Storm Slab avalanches are the release of a cohesive layer (a slab) of new snow that breaks within new snow or on the old snow surface. Storm-slabs typically last between a few hours and few days (following snowfall). Storm-slabs that form over a persistent weak layer (surface hoar, depth hoar, or near-surface facets) may be termed Persistent Slabs or may develop into Persistent Slabs.
Wet Slabs
Wet Slab avalanches are the release of a cohesive layer of snow (a slab) that is generally moist or wet when the flow of liquid water weakens the bond between the slab and the surface below (snow or ground). They often occur during prolonged warming events and/or rain-on-snow events. Wet Slabs can be very unpredictable and destructive.