Avalanche Forecast
Issued: Feb 9th, 2023 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Storm Slabs and Persistent Slabs.
dsaly,
Avalanche Canada
Stick to conservative terrain and avoid overhead avalanche hazard, the heavy load of new snow needs time to settle and bond.
Summary
Confidence
Avalanche Summary
On Wednesday, skiers triggered a large, size 2 avalanche near Ningunsaw. The Deep Persistent avalanche was triggered on an east aspect near ridgetop in a thin, rocky start zone and failed on basal facets.
On Wednesday and Thursday morning, avalanche control operators also reported natural and explosive-triggered wind and storm slab avalanches up to size 3, likely occurring with the recent heavy snowfall.
Evidence of a widespread natural avalanche cycle was observed throughout the region on Monday and Tuesday, with storm slabs and wind slabs observed to an impressive size 3 (very large). Many slabs started off dry but finished running as wet loose slides at the bottom of their runouts.
Snowpack Summary
40-70 cm recent storm snow covered older wind-affected surfaces and a supportive melt-freeze crust up to 1800 m and steep solar slopes. South-southwesterly winds have been creating wind-affected surfaces and wind slabs of varying age and reactivity on an ongoing basis.
Recent and forecast storm snow will form only the uppermost portion of 100-150 cm of storm snow from the past week settling over a layer of facets, crust, and previous wind-affected surfaces in alpine terrain. This interface remains somewhat in question under the patterns of continuous loading and successive natural avalanche cycles.
The mid and lower snowpack continues to bond and stabilize while a number of buried weak layers are still being tracked by professionals in the region, having produced a few large avalanches in the not-too-distant past.
Weather Summary
Thursday night
Continuing snowfall, 5-15 cm tapering Friday morning. South winds gusting to 60 km/hr. Treeline low temperature -5 C with freezing levels dropping below 500 m.
Friday
Mostly cloudy with isolated flurries, 5 cm. Storm totals 40-70 cm. Southwest winds easing to 20-30 km/hr. Treeline high temperature -3 C.
SaturdayFlurries increasing through the day, 5-10 cm. Southwest wind increasing to 60 km/hr with approaching storm. Treeline high temperature -2 C.
SundayHeavy snow, 20-40 cm. Southwest winds gusting over 100 km/hr. Treeline high temperature -2 C.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Don't let the desire for deep powder pull you into high consequence terrain.
- Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
- Use conservative route selection. Choose simple, low-angle, well-supported terrain with no overhead hazard.
Problems
Storm Slabs
Another 30 cm heavy snowfall Thursday likely triggered yet another natural avalanche cycle involving large storm slabs and wind slabs. Lingering storm slabs may still be reactive to skiers, with the most reactive deposits in wind-affected terrain.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Persistent Slabs
A deeply buried weak layer still presents a Low Probability/High Consequence situation. New snow and wind has been testing this weakness in the snowpack and the results still aren't in. This layer would be most likely to be triggered in places where the snowpack is shallow and rocky.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Feb 10th, 2023 4:00PM
