Avalanche Forecast
Issued: Jan 17th, 2023 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Storm Slabs and Loose Wet.
zryan,
Avalanche Canada
A significant storm will impact the region overnight bringing heavy snowfall, wind, and rain. Very dangerous avalanche conditions will exist on Wednesday. Choose simple, low-angled terrain free of overhead hazards.
Summary
Confidence
Moderate
Avalanche Summary
A natural avalanche cycle will likely occur overnight on Tuesday with heavy snowfall/rain and wind. This cycle may continue into the day on Wednesday. Human-triggered storm slabs will be very likely on Wednesday.
No recent avalanches have been reported in this region with limited reports coming out of these mountains. In the neighbouring region, several large (size 2-3) persistent slab avalanches occurred with explosive control on Monday. These avalanches failed on a weak facet layer formed in late December.
Several skier-triggered (size 1-2) persistent slab avalanches have been reported further inland around Terrace and Smithers over the past few days. These avalanches are failing on a weak layer of surface hoar in the upper meter of the snowpack. One of these slabs stepped down to a layer of weak, sugary, facetted crystals that were buried on December 23rd.
Snowpack Summary
A significant storm impacting the region will bring 40-60 cm of new snow to upper elevations by Wednesday afternoon. Fresh snow will be falling mostly on 20-50 cm of dry settling snow or refrozen or moist snow below 1000 m.
Weak layers that were reactive over the Christmas and New Year's period have shown signs of bonding and gaining strength. These include a surface hoar layer buried on Dec 28 found 50 to 100 cm deep and a facet layer buried on Dec 23 found 70 to 120 cm deep.
Weather Summary
Tuesday night
Cloudy with snowfall, 20 to 50 cm of accumulation. Alpine temperatures drop to a low of -2 °C. Ridge wind south 40 km/h gusting to 75 km/h. Freezing level 700 metres.
Wednesday
Mainly cloudy with snowfall, 10 to 20 cm of accumulation. Alpine temperatures reach a high of -2 °C. Ridge wind southwest 25-45 km/h. Freezing level 500 metres.
ThursdayCloudy with snowfall, 5 to 15 cm of accumulation. Alpine temperatures reach a high of -4 °C. Ridge wind southwest 30 - 55 km/h. Freezing level 600 metres.
FridayCloudy with flurries, 5-15 cm accumulation. Alpine temperatures reach a high of -1 °C. Ridge wind southwest 40-55 km/h. Freezing level 800 metres.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Avoid all avalanche terrain during periods of heavy loading from new snow, wind, or rain.
- Storm slabs in motion may step down to deeper layers resulting in large avalanches.
- Use conservative route selection. Choose simple, low-angle, well-supported terrain with no overhead hazard.
- As surface loses cohesion due to melting, loose wet avalanches become common in steeper terrain.
Problems
Storm Slabs
Heavy snowfall and wind will impact the region overnight on Tuesday and continue into Wednesday growing deep and reactive storm slabs. Human triggering will be very likely, particularly in wind-loaded terrain at upper elevations.
Keep in mind that storm slab avalanches have the potential to step-down to deeply buried weak layers, resulting in large and consequential avalanches.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Loose Wet
Heavy rain at lower elevations will create wet loose avalanches in steep terrain. Avoid travelling on steep slopes and overhead exposure to steep terrain.
Aspects: All aspects.
Elevations: Treeline, Below Treeline.
Likelihood
Expected Size
Valid until: Jan 18th, 2023 4:00PM
