Avalanche Forecast

Issued: Jan 6th, 2022 4:00PM

The alpine rating is considerable, the treeline rating is moderate, and the below treeline rating is low. Known problems include Wind Slabs.

Avalanche Canada rbuhler, Avalanche Canada

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Northerly outflow winds continue to be the main driver of the avalanche danger. Recently formed wind slabs may remain reactive to human triggering for longer than normal due to the presence of a weak layer below them. Use extra caution in wind exposed terrain. 

Summary

Confidence

Moderate - Uncertainty is due to the limited number of field observations.

Weather Forecast

Unsettled conditions are expected for Friday with both snow flurries and sunny breaks. A storm system reaches the region early Saturday and upwards of 30 cm is expected by Sunday afternoon in the south of the region while the north is currently only expected to receive 10-15 cm. 

Thursday Overnight: Snowfall up to 10 cm in the south with only flurries expected in the north, light variable wind, treeline temperature around -22 °C.

Friday: Flurries in the morning, sunny breaks in the afternoon, light to moderate N wind, treeline high around -24 °C.

Saturday: Snowfall 5-15 cm, moderate to strong W wind, treeline high around -22 °C.

Sunday: Snowfall 5-15 cm overnight, lingering snow flurries in the morning, strong to extreme SW wind, treeline high around -12 °C.

Avalanche Summary

No new avalanches were reported on Wednesday. On Tuesday, operators north of McBride reported two natural size 2 wind slabs which were formed by NE outflow wind loading.

Observations have been limited due to the cold conditions. If you are out in the mountains, let us know what you see by filling out a Mountain Information Network report! 

Snowpack Summary

Recently formed wind slabs are most likely to be found on south and westerly aspects, but older wind slabs may be found on all aspects. Recently formed wind slabs may remain reactive to human triggers for longer than is typical due to the weak facets (sugary snow) they are sitting on.

A crust that was formed at treeline elevations and below in early December has been reported in parts of this region. It can be found down 50-100 cm. There have been no recent reports of avalanches on this layer. While the layer is now dormant in the region, a large amount of new snow or warming temperatures have the potential to wake it up, and wind slab avalanches may still have the potential to step down to this layer in isolated areas. 

The base of the snowpack is composed of crusts and weak faceted grains, particularly in thin snowpack areas east of the divide. 

Terrain and Travel

  • Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
  • Be aware of highly variable recent wind loading patterns.
  • The best and safest riding will be on slopes that have soft snow without any slab properties.
  • Look for signs of instability: whumphing, hollow sounds, shooting cracks, and recent avalanches.
  • Keep your guard up at lower elevations. Wind slab formation has been extensive.

Problems

Wind Slabs

An icon showing Wind Slabs

Recent strong NE winds have likely formed reactive wind slabs on lee features at all elevations. These wind slabs are most likely to be found on south and westerly aspects, but older wind slabs may be found on all aspects. 

Wind slabs may remain reactive to human triggers for longer than is typical due to the weak facets (sugary snow) they are sitting on.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

1 - 2.5

Valid until: Jan 7th, 2022 4:00PM