Avalanche Forecast
Issued: Dec 5th, 2022 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs.
ldreier,
Avalanche Canada
Strong northwest wind at upper elevations will form reactive wind slabs, especially where it sits on weak feathery surface hoar. Pay attention to the wind and investigate the bond of the new snow.
Summary
Confidence
Avalanche Summary
No new avalanches have been observed or reported in this region. However, note that we have had very few field observations.
Snowpack Summary
Up to 30 cm of low-density snow covers older more settled snow. Down 40-60 cm is a melt-freeze crust from mid-November. To the east, in the Columbia and Kootenay-Boundary forecast regions, a layer of surface hoar (on a crust) down 40-70 cm has been quite reactive with extensive reports of whumpfing and cracking, several skier triggered and a few natural avalanches up to size 2. This layer is found within this forecast region, but we need more field observations to determine its extent and sensitivity. Snowpack depths exceed 100 cm at upper elevations.
Weather Summary
Monday night
Cloudy with up to 5 cm low-density snow. Northwest wind 20 km/h around treeline and up to 50 km/h at upper elevations. Treeline low temperature -14 °C.
Tuesday
Cloudy and cold, with isolated flurries, up to 5 cm low-density snow. Northwest wind 20-30 km/h around treeline and up to 50 km/h at upper elevations. Treeline high temperature -9 °C.
WednesdayMostly cloudy and cold, with isolated flurries. Southwest wind 20-30 km/h. Treeline high temperature -8 °C.
ThursdayMostly cloudy with isolated flurries and up to 5 cm low-density snow. Southwest wind 50-60 km/h. Treeline high temperature -8 °C.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
- Closely monitor how the new snow is bonding to the old surface.
- Potential for wide propagation exists, fresh slabs may rest on surface hoar, facets and/or crust.
Problems
Wind Slabs
Strong northwest winds at upper elevations will form fresh wind slabs overnight Monday to Tuesday and during the day on Tuesday. Up to 10 cm low-density snow will add to the existing loose snow that is available for transport. Expect fresh slabs to form where the wind picks up.
Reports further east describe a weak layer of surface hoar buried 40-60 cm deep (check out the Avalanche Forecast to the east). Skiers triggered several avalanches up to size 2 on this layer, and extensive whumpfing and cracking was reported. We have limited observations this year, but this problem could also be encountered in this avalanche forecast region. Keep an eye on the wind, slabs may quickly form wherever the wind encourages the fresh snow to bond; and with a weak layer of surface hoar below, reactive slabs may be more widespread, extend into treeline elevations, and be more reactive than expected in sheltered areas.
Aspects: North, North East, East, South East, South, South West.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Dec 6th, 2022 4:00PM
