Avalanche Forecast

Issued: Dec 18th, 2021 4:00PM

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

Avalanche Canada bchristie, Avalanche Canada

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Sheltered areas with soft snow have the best riding, and the lowest avalanche hazard. If you are planning to head into bigger, more committing terrain, take your time gathering information, and keep a constant watch for signs of instability. 

Summary

Confidence

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

Weather Forecast

Generally cold and calm, with a northerly flow. Winds pick up on Monday night, shifting to the west preceding the next weather system.

Saturday Night: Partly cloudy. 0-2 cm of snow expected. Strong winds at lower elevations ease off, winds generally moderate from the northeast, shifting to northwest. Treeline low around -17 °C. 

Sunday: Sunny. No new snow expected. Light to moderate northwest winds. Treeline high around -16 °C.

Monday: Scattered clouds. No new snow expected. Moderate northwest winds, with possible strong winds at low elevations in the north end of the region. Treeline high around -17 °C.

Tuesday: Mostly cloudy. Light snowfall, with isolated areas of moderate snowfall. Extreme west winds, trending to northwest at higher elevations. The far south end of the region may see lower wind speeds at lower elevations. Treeline high around -13 °C.

Avalanche Summary

No new avalanches were reported on Saturday, but there are very few professional operations or recreationalists reporting on conditions. 

If you feel like you have good information, or even just good vibes and good pictures to share, consider making a quick post on the Mountain Information Network:)

If your area has seen moderate to strong winds at low elevations, watch out for fresh, reactive wind slabs where you wouldn't have expected them earlier this week. These winds are forecast to be from the northeast, so slabs will most likely be formed on southwest aspects, but also check for cross-loading. Winds at lower elevation can be especially variable with local terrain, so you won't be able to know (where wind slabs might be), until you go (and check for signs of instability).

Check out our forecaster blog for some thoughts on the snowpack at this point in the season. Persistent weak layers are still on our minds.

Snowpack Summary

5-10 cm of low density new snow has fallen in the last 24 hours. This new snow covers old wind slabs formed over the last week. Given the variable nature of the recent wind, slabs should be expected on all aspects in exposed terrain at treeline and in the alpine.

In the south half of the region, some increased wind at lower elevations means you may find some reactive wind slabs at lower elevations where you wouldn't usually expect them. 

Check out this post from the Mountain Information Network (MIN) by our North Rockies field team for a great summary of conditions at the Anzac on Friday, and this post for Torpy on Thursday.

Snowpack depth at treeline typically ranges from 50-250 cm, with the shallower value mainly on the eastern side of the range. The alpine snowpack typically ranges from 150-250 cm. 

Terrain and Travel

  • Be careful with wind loaded pockets, especially near ridge crests and roll-overs.
  • If you are increasing your exposure to avalanche terrain, do it gradually as you gather information.
  • Avoid terrain traps where the consequence of any avalanche could be serious.
  • Recent wind has varied in direction so watch for wind slabs on all aspects.

Problems

Wind Slabs

An icon showing Wind Slabs

These wind slabs have been less reactive in the last few days, but could still be triggered if you hit the wrong spot. 

Watch out for fatter looking pockets or pillows of snow, especially right at ridge-crests, or places where the terrain rolls away from you.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

1 - 2.5

Valid until: Dec 19th, 2021 4:00PM