A Special Public Avalanche Warning is in effect for this region. Strong winds and warming will maintain high danger even though snow amounts may start to taper off.
Confidence
Moderate - Freezing levels are uncertain on Friday
Weather Forecast
THURSDAY NIGHT: Around 15 cm new snow above 1600 m.FRIDAY: A mix of sun and cloud in the morning with heavy rain/snow developing in the afternoon (amounts of about 20 cm/mm). Very strong southerly winds (up to 100 km/h at ridgetop). Freezing level around 1700 m.SATURDAY: A mix of sun and cloud. Winds becoming light southwesterly. Freezing level around 900 m.SUNDAY: 20 cm or so new snow with a freezing level of around 1200 m. Strong southerly winds.
Avalanche Summary
A widespread natural avalanche cycle was reported on Wednesday and Thursday. Natural avalanches are likely to continue on Friday. Human-triggered avalanches will remain a concern over the weekend.
Snowpack Summary
Snowfall beginning Sunday has deposited up to 130 cm in the Sea to Sky region. Strong to extreme southwesterly winds have accompanied the new snow and the weather forecast is calling for additional snowfall amounts to accumulate. Buried under the new snow is a weak surface layer sitting over 20-30 cm of low density faceted snow. The new snow is not bonding well with the old surface layer, has slab-like properties, and is reacting to skier traffic.Prior to this storm, alpine snowpack depths varied around 150-200 cm, with an early November crust at bottom of the snowpack (down 100-120 cm). This crust appears to be breaking down at higher elevations and has been unreactive to snowpack tests. Snowpack depths disappear quickly with decreasing elevations (starting around 1800 m).
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.