Avalanche Forecast
Issued: Jan 19th, 2021 4:00PM
The alpine rating is Wind Slabs and Cornices.
, the treeline rating is , and the below treeline rating is Known problems includeA windy night has likely resulted in fresh wind slabs reverse loaded into atypical alpine features. Watch for these pockets especially at ridge crests and on steep roll-overs.
Summary
Confidence
High -
Weather Forecast
TUESDAY night: Flurries, trace, strong to extreme ridgetop wind easing to light northwest, freezing level 500 m.
WEDNESDAY: Mix of sun and cloud, light ridgetop wind, alpine high -4, freezing level 800 m.
THURSDAY: Mix of sun and cloud, light wind, alpine high -7, freezing level 700 m.
FRIDAY: Sunny, light wind, alpine high -7, freezing level 500 m.
Avalanche Summary
A few small wind slab and wet loose avalanches were reported on Sunday and Monday. Explosive control targeting cornices on Friday and Saturday produced size 2 results, some triggering deep slabs on the rocky slopes below.Â
There has been significant deep persistent slab activity this month. During a widespread avalanche cycle last week, several storm slabs stepped down to deeper weak layers resulting in very large (size 3-4) deep persistent slab avalanches (see these photos from Panorama Ridge). On Jan 9, a large (size 3) avalanche was remotely triggered by skiers on Cowboy Ridge near Whistler. The avalanche occurred on a north to northwest aspect at around 1900 m. The crown was up to 200 cm deep and was approximately 200 m wide. See this MIN for photos and more information. A similar avalanche was remotely triggered by skiers on a nearby westerly slope a few days before (see this MIN).
Snowpack Summary
Ski quality in the extensively wind affected alpine has been widely referred to as chalky. Soft snow may be found in sheltered areas around treeline. A widespread surface crust exists below 1900 m and on south-facing slopes.
Remnants of a melt-freeze crust from early December may be found around 200 cm deep in the snowpack. Several large natural and human triggered avalanches failed on this layer earlier this month. Recent reports and snow profiles suggest that it is decomposing and/or bonding to surrounding snow and trending dormant... for now at least.
Terrain and Travel
- Be carefull around freshly wind loaded features.
- Use extra caution around cornices: they are large, fragile, and can trigger slabs on slopes below.
Problems
Wind Slabs
Strong overnight wind from the northwest has likely blown any available loose snow into small but reactive fresh wind slabs in leeward terrain features at upper elevations.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Cornices
Cornices have grown large, saggy and fragile. A few recent cornice falls have triggered avalanches on the slopes below.
Aspects: North, North East, East, North West.
Elevations: Alpine.
Likelihood
Expected Size
Valid until: Jan 20th, 2021 4:00PM