Avalanche Forecast
Issued: Dec 13th, 2022 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs.
zryan,
Avalanche Canada
Fresh wind slabs are expected to form throughout the day as northwesterly winds redistribute the surface snow into lee areas in the alpine and treeline.
Keep in mind that if triggered, wind slabs have the potential to 'step down' to the weak lower snowpack, creating larger than expected avalanches.
Summary
Confidence
Avalanche Summary
On Saturday, a natural storm slab avalanche was observed on a west aspect at treeline.
On Monday, several natural size 1 glide slab avalanches were observed below treeline on rock slabs near the highway.
Looking forward to Wednesday, increasing northwesterly winds are expected to redistribute the surface snow into fresh wind slabs anywhere it remains loose and powdery.
Observations are limited this time of year. Keep posting your observations to the MIN; it helps strengthen our information gathering.
Snowpack Summary
In deeper zones near ridges, the snowpack is around 120 to 170 cm, which is low for early December. Alpine terrain in windy areas is scoured and bare.
Surface: Large surface hoar has grown on the surface in many areas. A breakable sun crust exists on steep solar aspects. Boot top powder in deep areas. Same old crusts, facets, and rocks on wind-scoured slopes.Upper-pack: In sheltered areas below the fresh snow is well-developed surface hoar. Generally, there's 40 to 70 cm of low-density and faceting (aka weak) snow in the upper pack.Mid-pack: November crust, with a layer of soft facets above. This is the primary weak layer, found pretty much halfway down.Lower-pack: a mixture of old crusts and facets but some suggest that these layers are a bit harder or stronger than what's found in other regions (e.g. Duffy or Hurley).
Weather Summary
Tuesday
Clear periods with isolated flurries. Alpine temperatures drop to a low of -6 °C. Ridge wind northeast 15 km/h. Freezing level at valley bottom.
Wednesday
Sunny. Alpine temperatures reach a high of -2 °C. Ridge wind northeast 15-30 km/h. Freezing level rises to 500 metres.
ThursdaySunny with cloudy periods. Alpine temperatures reach a high of 1 °C. Ridge wind north 15 km/h gusting to 60 km/h. Freezing level rises to 1900 metres.
FridaySunny with a strong alpine temperature inversion. Alpine temperatures reach a high of 2 °C. Mostly light ridge wind occasionally gusting to 30 km/h from the northwest. Freezing level rises to 2400 metres.
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.
- The best and safest riding will be on slopes that have soft snow without any slab properties.
- Wind slabs may be poorly bonded to the underlying crust.
Problems
Wind Slabs
Northwesterly winds are expected to form fresh, reactive wind slabs in the alpine and treeline. Watch for pockets of wind slab on the lee side of ridges or ribs.
With the sugary, faceted, and weak snowpack wind slabs could step down to the middle of the snowpack, resulting in larger than expected avalanches.
Aspects: North East, East, South East, South, South West, West.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Dec 14th, 2022 4:00PM
