Avalanche Forecast
Issued: Jan 19th, 2023 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs and Deep Persistent Slabs.
cgarritty,
Avalanche Canada
Keep an eye open for wind slabs forming in unusual places as northwest winds pick up tomorrow, particularly in the alpine and exposed treeline.Surface conditions aside, the weak basal snowpack continues to demand conservative terrain selection. Keep up the safe group management decisions and avoiding shallow rocky start zones like the plague.
Summary
Confidence
Avalanche Summary
On Tuesday and Wednesday, human-triggered wind slabs up to size 1 were reported at treeline and above.
Ski cutting in the Fernie area on Monday yielded small (size 1) wind slab releases after the area received 15 cm of new snow. Natural dry loose releases from steep alpine terrain reached size 1.5.
Snowpack Summary
Roughly 10 cm of recent snow has been getting moved into small wind slabs in exposed areas and otherwise settling on older wind-affected surfaces above 1800-2000 m and on a crust below this elevation.
A crust/facet layer (2-15 cm thick at TL elevation) is down 50-90 cm. Where it's thickest, it caps the settled and consolidated mid-snowpack.
Another crust/facet layer is down 70-150 cm. Below this crust, the basal snowpack is weak and faceted.
Weather Summary
Thursday night
Cloudy with isolated flurries. Light to moderate southwest winds, increasing into the morning.
Friday
Mainly cloudy. Light southwest or northwest winds, more northerly with elevation and potentially strong in the alpine. Treeline high temperatures around -5.
SaturdayIncreasing cloud with scattered flurries bringing less than 5 cm of new snow in the afternoon. Finishing quickly in the evening. Light to moderate southwest winds, increasing over the day. Treeline high temperatures around -5.
SundayMainly sunny. Light to moderate northwest winds. Treeline high temperatures around -6.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Avoid thin areas like rock outcroppings where you're most likely to trigger avalanches failing on deep weak layers.
- In areas where deep persistent slabs may exist, avoid shallow or variable depth snowpacks and unsupported terrain features.
- Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
Problems
Wind Slabs
Small wind slabs at treeline and above may remain reactive to human triggering on Wednesday. Watch for possible reverse loading south to east aspects as northwest winds pick up on Friday.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Deep Persistent Slabs
Weak, faceted grains make up the basal snowpack. Where supportive to riders, a melt-freeze crust may be providing a bridging effect, making it more difficult to trigger deeper layers. Any avalanche triggered this deep will likely be large and destructive. Be especially suspicious of shallow, rocky, or cross-loaded areas with variable snow depths.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Jan 20th, 2023 4:00PM
