Avalanche Forecast
Issued: Feb 3rd, 2020 5:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Cornices and Wind Slabs.
MBender,
Avalanche Canada
Carefully evaluate terrain for overhead cornice hazard and areas where wind slabs may remain reactive to human triggering.
Summary
Confidence
Weather Forecast
Monday Night: Mainly clear. Light north wind. Alpine high -10 C.
Tuesday: Flurries, accumulation 5-10 cm. Moderate southwest wind. Alpine high -6 C.
Wednesday: Flurries, accumulation 5-15 cm overnight Tuesday night into Wednesday and an additional 5 cm through Wednesday. Moderate to strong west wind. Alpine high -2 C. Freezing level 1000 m.
Thursday: Flurries, accumulation 10-15 cm. Light moderate west wind, Alpine high -2 C. Freezing level 1000 m.
Avalanche Summary
On Sunday there were reports of explosives controlled wind slab and storm slab avalanches to size 2 in the alpine. There was also a report of a size 3.5 naturally triggered deep persistent avalanche on a northwest aspect at 2600m. This would have run during or just after the storm on the weekend.
On Saturday, a widespread natural cycle and extensive explosive work produced cornice and storm slab avalanches size 2-3.
Additionally, natural and explosive triggered deep persistent slab avalanches size 3-4 have been reported in the Lillooet River valley north of Pemberton, at the eastern border of the region.
Snowpack Summary
Extreme southwest wind leading into last weekend has scoured windward aspects, formed loaded pockets up to 150 cm deep in alpine lees and contributed to rapid cornice growth. Below 1900 m, recent snow overlies a thick crust and tapers quickly with elevation.
Weak faceted grains and crusts near the base of the snowpack have not been an active avalanche problem recently, despite significant new snow loads. They are still on our radar, especially in inland parts of the region.
Terrain and Travel
- Carefully evaluate bigger terrain features on an individual basis before committing to them.
- Extra caution is needed around cornices under the current conditions.
- Pay attention to cornices and give them a wide berth when traveling on or below ridges.
- Recent wind has varied in direction so watch for wind slabs on all aspects.
Problems
Cornices
Significant cornice growth has been observed. Recent natural and explosive triggered cornices have produced large avalanches (size 2-3). Avoid overhead cornice hazard and stay well back from lee side of ridges.
Aspects: North, North East, East, South East, West, North West.
Elevations: Alpine.
Likelihood
Expected Size
Wind Slabs
Wind changing in direction from southwest to northwest has loaded new features which may be sensitive to human triggering.
Aspects: North, North East, East, South East, South, North West.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Feb 4th, 2020 5:00PM
