Avalanche Forecast
Regions: Sea To Sky.
The weekend storm produced 4 to 8 cm of snow with wind out of the southwest, wind slabs may begin to form in unusual locations as wind switches to the north Sunday night into Monday. Watch for wind-loaded pockets, especially around ridge crest and in extreme terrain.
Confidence
Moderate - Uncertainty is due to the speed, direction, or duration of the wind and its effect on the snowpack.
Weather Forecast
SUNDAY NIGHT: Freezing level at valley bottom, no new snow expected, light northeast wind at most elevations with moderate gusts at ridge top.
MONDAY: A few clouds in the morning giving way to clear skies in the afternoon, no new snow expected, moderate northeast wind, daytime high temperature at 1500 m around -8 C.
TUESDAY: Clear skies, no new snow expected, moderate northeast wind, daytime high temperature at 1500 m around -10 C.
WEDNESDAY: Scattered cloud cover, no new snow expected, light variable wind, daytime high temperature at 1500 m warming slightly to -8 C.
Avalanche Summary
Thin wind slabs were reactive to ski cutting just below ridge crests Saturday afternoon.
On Thursday, a natural icefall triggered a size 2.5 avalanche on the slope below. This avalanche was on a northeast aspect at 2100Â m.
On Wednesday, a size 1 natural cornice fall was observed on an east aspect at 2200Â m. It was in extreme terrain and did not pull a slab on the slope below.
Snowpack Summary
The weekend storm produced 4 to 8 cm of snow with strong southwest wind that likely formed thin wind slabs in exposed terrain.Â
The mid-February crust is down 10 to 30Â cm . This melt-freeze crust is reported to exist on all aspects and elevations, except for some of the highest elevation polar aspects. Facets have been observed above the crust on polar aspects.
The late-January crust/facet/surface hoar interface is buried down 40 to 100Â cm. This layer was most reactive between 1700 m and 2000 m. While this layer now appears to be dormant in many parts of the region, it may be possible to trigger it with a large load or in shallow snow pack areas at upper treeline or lower alpine features on polar aspects.
Terrain and Travel
- Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
- Closely monitor how the new snow is bonding to the crust.
- Be aware of the potential for large avalanches due to the presence of buried persistent weak layers.
Avalanche Problems
Wind Slabs
4 to 8 cm of snow fell over the weekend accompanied by southwest wind. The wind is expected to switch to the North Sunday night, which may begin to form slabs in unusual locations.
Aspects: All aspects.
Elevations: Alpine.
Likelihood: Possible
Expected Size: 1 - 2
Persistent Slabs
The late-January weak layer is down 40 to 100 cm and was most reactive between 1700 and 2000 m. It is now likely dormant in many areas. It is likely only possible to trigger on polar aspects at upper treeline or lower alpine where the mid February crust is thinner and not bridging.
Aspects: North, North East, East, West, North West.
Elevations: Alpine, Treeline.
Likelihood: Unlikely
Expected Size: 2 - 3