Avalanche forecast

Northwest Inland

Jan 13, 2017Avalanche Canada
View on map
Archived · expired 10 years ago

Avalanche danger

Fri
Sat
Alpine
3 · Considerable
Treeline
2 · Moderate
Below
2 · Moderate
Open full map

Highlights

The storm this weekend is currently expected to only bring light amounts. Danger is still expected to rise on account of strong winds and rapidly rising temperatures.

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible - Likely
    Size
    1–2
    Strong to extreme winds may redistribute any remaining loose surface snow into fresh wind slabs, adding to an ongoing wind slab problem. Wind slabs may step down to deeper weak layers resulting in surprisingly large avalanches.

  • Deep Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    2–3
    In most areas this is a lower probability, high consequence scenario and requires a conservative approach to larger terrain features. Avoid likely trigger spots such as steep and rocky areas with a shallow snowpack.

Confidence

Moderate - Intensity of incoming weather systems is uncertain on Saturday

Weather Forecast

Friday: Flurries. Ridgetop winds increasing to around 70 km/h from the southwest. Temperatures rising from around -20C in the morning to -10C in the afternoon. Friday night: Up to 5 cm new snow with continued strong winds and rising temperatures.Saturday: a further 5 cm new snow expected, ridgetop winds around 70 km/h from the southwest and treeline temperatures touching 0C. Freezing level expected to be around 1200 m.Sunday: A break in the storm with flurries, winds around 40 km/h from the southwest, freezing level around 1200 m.

Avalanche Summary

On Tuesday, a skier accidentally triggered a size 2 wind slab on a 34 degree southwest facing slope at treeline. This avalanche occurred a few kilometres east of the Kispiox river valley. A natural avalanche also ran about that time near Ningunsaw. It was reported as a size 2.5 running on basal facets on a southwest aspect at 1700 m.

Snowpack Summary

Recent wind transport has shifted low density snow into wind slabs at upper elevations. Recently temperatures have been warmer in the alpine than in the valley, which may have made the alpine snow slightly firmer (in sheltered locations - it's already firm where it's been drifted by wind). Snow depth at treeline varies from about 1 m in most areas to 2 m in deeper snowpack areas in the south and west of the region. The shallow snowpack areas mostly consist of weak facetted or sugary grains beneath hard slabs. These hard slabs may produce surprisingly long fractures resulting in large avalanches, and in some instances they may step down to weak faceted snow crystals near or at the ground. In addition to the facets, a thick layer of buried surface hoar may be found 30-40 cm below the surface. There is another persistent weakness that formed during the early December cold snap which is now about 50-70 cm deep.

Regions covered