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Avalanche Forecast

Jan 31st, 2022–Feb 1st, 2022
Alpine
3: Considerable
The avalanche danger rating in the alpine will be considerable
Treeline
2: Moderate
The avalanche danger rating at treeline will be moderate
Below Treeline
2: Moderate
The avalanche danger rating below treeline will be moderate
Alpine
2: Moderate
The avalanche danger rating in the alpine will be moderate
Treeline
2: Moderate
The avalanche danger rating at treeline will be moderate
Below Treeline
2: Moderate
The avalanche danger rating below treeline will be moderate
Alpine
2: Moderate
The avalanche danger rating in the alpine will be moderate
Treeline
2: Moderate
The avalanche danger rating at treeline will be moderate
Below Treeline
1: Low
The avalanche danger rating below treeline will be low

Regions: South Rockies.

Recently formed wind slabs are expected to remain touchy on Tuesday, especially where they overlie surface hoar or a crust. Loose dry avalanches should be expected on steep slopes.

Confidence

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

Weather Forecast

Unsettled conditions are expected on Tuesday as Arctic air shifts southward. 

Monday Night: Partly cloudy, light to moderate NW wind, treeline temperature dropping to around -14 C°.

Tuesday: Mainly cloudy with snow flurries up to 5 cm, light to moderate NW wind, treeline high around -14 C°.

Wednesday: Mainly sunny, light variable wind, treeline high around -16 C°.

Thursday: Mainly sunny, light to moderate variable wind, treeline high around -8 C°.

Avalanche Summary

An early report on Monday shows ski cutting and explosives triggering small storm slabs and loose dry avalanches. Neighbouring regions were seeing some natural wind slabs and loose dry activity during the storm. 

Snowpack Summary

Up to 20 cm of new snow has buried heavily wind affected snow surfaces in exposed terrain, a melt-freeze crust at low elevations and on solar aspects extending into the alpine, and surface hoar in sheltered terrain. The January 18 melt-freeze crust extends up to around 2000 m elevation and can be found down around 20 cm.  

The early December crust/facet persistent weak layer is now 100-200 cm deep. This layer produced numerous very large avalanches during the third week of January but is now considered dormant after a week of cold, dry weather. While this layer is not currently considered a front page avalanche problem, we continue to track it and expect it will wake up again with major warming or a large storm event. This recent forecaster blog goes into more details on the layer.

Terrain and Travel

  • Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
  • Wind slabs may be poorly bonded to the underlying crust.
  • Continue to make conservative terrain choices while the storm snow settles and stabilizes.
  • Be aware of the potential for loose avalanches in steep terrain where snow hasn't formed a slab.

Avalanche Problems

Wind Slabs

The new snow is expected to be most reactive in wind loaded terrain, especially where it overlies surface hoar and/or a crust. The wind was recently blowing from the SW during the storm but has now shifted to the NW so wind slabs should be expected on most aspects.

Aspects: North, North East, East, South East, South, South West, North West.

Elevations: Alpine, Treeline.

Likelihood: Likely

Expected Size: 1 - 2