Avalanche Forecast
Issued: Mar 1st, 2021 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs.
cgarritty,
Avalanche Canada
Continued snowfall and elevated winds should keep our wind slab problem alive and well for the coming days. Seek out sheltered snow at lower elevations for the best quality and safest skiing and riding. Be ready to back off to simple terrain if snowfall exceeds forecast amounts.
Summary
Confidence
Weather Forecast
MONDAY NIGHT: Cloudy with continuing flurries bringing another 5-10 cm of new snow. Strong southwest winds.
TUESDAY: Cloudy but clearing with easing flurries bringing up to 5 cm of new snow and 4-day totals to about 50 cm. Moderate to strong southwest winds, easing over the day. Alpine high temperatures around -12.
WEDNESDAY: Mainly cloudy with isolated flurries and a trace of new snow. Light to moderate east winds. Alpine high temperatures around -12.
THURSDAY: Mainly cloudy with isolated flurries and a trace of new snow. Light variable winds. Alpine high temperatures around -11.
Avalanche Summary
Observations from the ongoing stormy period are still limited, due in part to a closure on the South Klondike Highway caused by a large natural avalanche occurring in a crossloaded gully above the road.
This event speaks well to the dangerous conditions brought on by new snow and wind. MIN reports such as this one from Tally Ho give a good idea of a reactive upper snowpack anywhere wind has been able to reach, even quite low elevations.
Looking forward, expect continued snowfall and strong wind to maintain dangerous avalanche conditions over the next couple of days, gradually stabilizing as wind slabs begin to bond with the surface and lose their reactivity.
Snowpack Summary
Up to 20 cm of new snow is expected to accumulate in the region by the end of the day on Tuesday, bringing 4-day snowfall totals in the region to around 50 cm. Strong to extreme southwest winds have and will continue to play a big role in redistributing this snow into thicker, reactive wind slabs in leeward and crossloaded terrain features.
By Tuesday afternoon, 100 or more cm of accumulated snow may overlie a layer of surface hoar in sheltered areas, previously reported here and here. Given its new depth and the lack of avalanche activity attributed to it, this layer may prove to be a transient weakness that has since been overshadowed by new wind slab development.
The lower snowpack is strong around White Pass, but inland areas like the Wheaton Valley likely have a thinner and weaker structure.
Terrain and Travel
- Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
- Recent wind has varied in direction so watch for wind slabs on all aspects.
- Avoid exposure to overhead avalanche terrain during periods of heavy loading from new snow, wind or rain.
Problems
Wind Slabs
Expect to find reactive wind slabs to the lee of the wind and in crossloaded features if you're nearing exposed terrain. A steady supply of new snow and wind through Tuesday (plus lots of recent snow available for transport) should keep this problem quite active for the near term, then gradually diminishing toward the end of the forecast period.
Aspects: North, North East, East, South East, West, North West.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Mar 3rd, 2021 4:00PM
