Avalanche Forecast
Issued: Jan 1st, 2021 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Storm Slabs and Persistent Slabs.
mconlan,
Avalanche Canada
Waves of storms are impacting the region. An avalanche cycle is expected to occur this weekend. Travel in avalanche terrain is not recommended.
Summary
Confidence
Weather Forecast
FRIDAY NIGHT: Cloudy with snowfall, accumulation 10 to 20 cm, 60 to 80 km/h southwest wind, alpine temperature -3 C, freezing level 900 m.
SATURDAY: Cloudy with snowfall, accumulation 15 to 25 cm, 80 km/h southwest wind, alpine temperature -3 C, freezing level 1000 m dropping to 700 m.
SUNDAY: Cloudy with snowfall, accumulation 20 to 30 cm, 40 to 60 km/h southwest wind, alpine temperature -6 C.
MONDAY: Cloudy with snowfall, accumulation 5 to 10 cm, 40 to 60 km/h south wind, alpine temperature -6 C.
Avalanche Summary
We received reports of the new snow being very reactive to human traffic on Friday. A natural avalanche cycle is expected to occur at some point during this stormy period, once sufficient snow loads the buried weak layers described in the snowpack summary. Avalanches are very likely to be triggered naturally and/or by riders this weekend.
Snowpack Summary
A hefty storm is impacting the region this weekend. 20 to 30 cm of snow has accumulated so far and upwards of 60 cm more snow may accumulate by the end of the weekend. Storm slabs are expected to be rapidly forming. The snow is falling with strong southwest wind, which is likely also rapidly forming wind slabs in exposed terrain.
All of this snow is loading two layers of weak and feathery surface hoar, found between 30 and 70 cm deep. The surface hoar was reported as being widespread prior to burial and the upper layer may sit on a melt-freeze crust from warm air on Boxing Day and/or from sunny skies.
Around 100 to 200 cm deep, a hard melt-freeze crust from early December may have weak and sugary faceted grains around it. These weak layers are likely the culprit of avalanche activity last weekend in the Nass Valley, Sterling, and Beaupre riding areas.
The early-November melt-freeze crust is over 200 cm deep and may have faceted grains above it in parts of the region, particularly in the north. The last reported avalanche activity was near Ningunsaw on December 11.
Terrain and Travel
- Travel in alpine terrain is not recommended.
- Avoid all avalanche terrain during periods of heavy loading from new snow and wind.
- Avoid exposure to overhead avalanche terrain, avalanches may run surprisingly far.
- Be aware of the potential for large avalanches due to the presence of buried surface hoar.
Problems
Storm Slabs
Storm totals may reach 60 cm by Saturday afternoon, with the most snow expected in the west of the region. Storm and wind slabs are likely building rapidly and they are loading buried weak layers. An avalanche cycle is expected to occur at some point during the next few days, producing very dangerous avalanche conditions.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Persistent Slabs
Numerous weak layers may exist in the top half of the snowpack, including surface hoar and faceted grains over a melt-freeze crust. These layers were recently triggered in riding areas north of Terrace and the likelihood of avalanches across the region will increase during this stormy period.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Jan 2nd, 2021 4:00PM
