Avalanche Forecast
Regions: Coquihalla, Manning, Skagit.
The potential for a temperature inversion and sun on Tuesday means loose wet avalanches may occur on steep slopes. Be alert to changes in aspect, elevation, and time of day.
The snowpack is shallow and early-season hazards are abundant, travel carefully!
Confidence
Moderate
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 Tuesday, the avalanche problem will likely be more confined to wind-loaded areas at upper elevations.
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: 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
Monday night
Cloudy with clear periods. Alpine temperatures drop to a low of -6 °C. Ridge wind light to 15 km/h from the north. Freezing level at valley bottom.
Tuesday
Cloudy with sunny periods. Alpine temperatures reach a high of -3 °C. Ridge wind northwest 15 km/h. Freezing level rises to 900 metres.
WednesdaySunny with cloudy periods. Alpine temperatures reach a high of -3 °C. Ridge wind northeast 25-40 km/h. Freezing level rises to 900 metres.
ThursdayA mix of sun and cloud. Alpine temperatures reach a high of -4 °C. Ridge wind northeast 25 km/h. Freezing level rises to 600 metres.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Back off slopes as the surface becomes moist or wet with rising temperatures.
- Avoid steep, rocky, and wind effected areas where triggering slabs is more likely.
- The best and safest riding will be on slopes that have soft snow without any slab properties.
Avalanche Problems
Loose Wet
Wet loose avalanches may occur if warm temperatures and sun weaken the upper snowpack.
Glide slabs have been reported at lower elevations on rock slabs. These slabs are most likely to release when temperatures are warm or sun is strong.
Aspects: South East, South, South West, West.
Elevations: All elevations.
Likelihood: Possible
Expected Size: 1 - 2
Wind Slabs
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: All aspects.
Elevations: Alpine.
Likelihood: Unlikely
Expected Size: 1 - 2.5