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Avalanche Forecast

Archived

Dec 11th, 2022–Dec 12th, 2022

Alpine
Natural avalanches unlikely, human triggered possible.
Treeline
Natural avalanches unlikely.
Below Treeline
Natural avalanches unlikely.
Alpine
Natural avalanches unlikely.
Treeline
Natural avalanches unlikely.
Below Treeline
Natural avalanches unlikely.
Alpine
Natural avalanches unlikely.
Treeline
Natural avalanches unlikely.
Below Treeline
Natural avalanches unlikely.

Regions

Coquihalla, Manning, Skagit.

For the best riding seek out sheltered slopes where the recent storm snow hasn't been wind-affected.

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.

Looking forward to Monday, we expect storm slab activity to drop off with cooling temperatures. The avalanche problem will likely be more confined to wind-loaded areas at upper elevations. Be cautious around these wind slabs as they may remain reactive to human triggering.

Keep sharing your observations via 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

Sunday night

Clear periods. Alpine temperatures reach a low of -11 °C. Ridge wind northeast 20 km/h. Freezing level at valley bottom.

Monday

Sunny with cloudy periods. Alpine temperatures reach a high of -7 °C. Ridge wind northeast 15-30 km/h. Freezing level rising to 400 meters.

Tuesday

Cloudy with sunny periods. Alpine temperatures reach a high of -3 °C. Ridge wind north 10 km/h. Freezing level rising to 800 meters.

Wednesday

A mix of sun and cloud. Alpine temperatures reach a high of -2 °C. Ridge wind northeast 15 km/h. Freezing level rising to 800 meters.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

  • Seek out sheltered terrain where new snow hasn't been wind-affected.
  • Stay off recently wind loaded slopes until they have had a chance to stabilize.
  • The best and safest riding will be on slopes that have soft snow without any slab properties.

Problems

Wind Slabs

Wind Slab avalanches are the release of a cohesive layer of snow (a slab) formed by the wind. Wind typically transports snow from the upwind sides of terrain features and deposits snow on the downwind side. Wind slabs are often smooth and rounded and sometimes sound hollow, and can range from soft to hard. Wind slabs that form over a persistent weak layer (surface hoar, depth hoar, or near-surface facets) may be termed Persistent Slabs or may develop into Persistent Slabs.