Avalanche Forecast
Issued: Feb 14th, 2022 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Persistent Slabs and Wind Slabs.
wlewis,
Avalanche Canada
Don't rely on surface conditions for clues to where the tricky persistent problem still exists. Open slopes at treeline are the most concerning, where buried surface hoar may be preserved.
Whumpfing, shooting cracks and recent avalanches are clear signs of an unstable snowpack.
Summary
Confidence
Moderate - Forecast snowfall amounts are uncertain. Uncertainty is due to the fact that persistent slabs are particularly difficult to forecast.
Weather Forecast
The cold front moves out of the region tonight, light flurries continue Tuesday. A high pressure builds Wednesday, bringing mostly dry conditions and scattered cloud.
MONDAY NIGHT: Cloudy with light snowfall delivering 5 cm by morning. A chance of enhanced precipitation around Fernie. Light westerly winds. Freezing levels around 1000m.Â
TUESDAY: Mostly cloudy with light westerly winds. Chance of flurries. Freezing levels reach 1200m. Alpine high of -3. Tuesday night will see light accumulation overnight, 2-8 cm.Â
WEDNESDAY: A mix of sun and cloud with light westerly winds. Freezing levels reach 1300m, alpine high of -2.Â
THURSDAY: Increasing cloudy with strong westerly winds. Chance of flurries. Freezing levels rise rise toward 2000 m. Alpine high of 0.Â
Avalanche Summary
A large persistent slab avalanche was reported in the Steeples on Saturday afternoon, on a south facing aspect at 2300 m. This avalanche had wide propagation and ran 2 km in length and is believed to have occurred on the late January persistent weak layer, crowns were estimated at 50 cm deep.Â
Several natural and human triggered wind slab avalanches to size 2 have been reported as recently as Saturday, on north through east facing slopes.Â
Snowpack Summary
Light snowfall will overly dense wind effected surfaces in exposed terrain at treeline and alpine elevations. In sheltered areas and lower elevations, new snow will fall on a widespread melt freeze crust.Â
The late January interface is buried 15-40cm deep, and consists of a melt-freeze crust at lower elevations and on solar aspects extending into the alpine. Surface hoar sits above the crust in sheltered areas at treeline and below.Â
The widespread January 18 rain crust is now around 40-100cm deep with weak faceted snow above. It is most prominent in the Lizard range. In heavily wind scoured areas at treeline and above this crust may even be found on the surface.Â
The snowpack below is well consolidated, with the early-December crust/facet persistent weak layer buried 100-200 cm deep. It is currently considered dormant. We expect this layer to become active later this season, check out the forecaster blog for more information.
Terrain and Travel
- Avalanche hazard may have improved, but be mindful that deep instabilities are still present.
- Look for signs of instability: whumphing, hollow sounds, shooting cracks, and recent avalanches.
- Be careful as you transition into wind affected terrain.
Problems
Persistent Slabs
- A layer of surface hoar from late January is buried 10-40 cm deep. On solar aspects and at lower elevations surface hoar sits over a melt freeze crust.
- A layer of facets over a crust from early January is buried 50-70 cm deep.
Treat sheltered open slopes at a treeline with extra caution where the surface hoar is most likely to be preserved - like cut blocks. Deeper instabilities could be triggered in shallow snow pack areas or by a large load such as a cornice or step down avalanche.
Avalanche activity is less likely where a thick and supportive crust sits on the surface.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Wind Slabs
Recent strong winds from the SW through NW have formed wind slabs in exposed terrain at higher elevations. These slabs are more reactive where they overlie buried surface hoar or a smooth crust.
Aspects: North, North East, East, South East, South, North West.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Feb 15th, 2022 4:00PM
