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Avalanche Forecast

Feb 20th, 2020–Feb 21st, 2020
Alpine
2: Moderate
The avalanche danger rating in the alpine will be moderate
Treeline
1: Low
The avalanche danger rating at treeline will be low
Below Treeline
1: Low
The avalanche danger rating below treeline will be low
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
2: Moderate
The avalanche danger rating below treeline will be moderate

Regions: South Columbia.

Moderate southerly winds may create small wind slabs that are possible to trigger in steep, convex terrain below ridgetops.

Confidence

High - The number, quality, or consistency of field observations is good, and supports our confidence.

Weather Forecast

THURSDAY NIGHT: Clear, moderate south wind, alpine temperature -13 C, freezing level below valley bottom.

FRIDAY: Mix of sun and cloud, moderate southwest wind, alpine temperature -8 C, freezing level 1100 m.

SATURDAY: 5-10 cm snow, moderate southwest wind, alpine temperature -7 C, freezing level 1000 m.

SUNDAY: Cloudy with flurries; 3-5 cm., light to moderate south wind, alpine temperature -9 C, freezing level 700 m.

Avalanche Summary

Numerous cornice falls on Tuesday had a variety of results. They mostly only entrained recent storm snow but a few did trigger slab avalanches up to size 2. Additionally, several skier triggered slab avalanches up to size 1.5 were reported primarily in wind affected terrain. 

Snowpack Summary

Clear and sunny skies have formed new surface hoar (size 3-10 mm.) on all but solar aspects where a new sun crust has been formed. This new interface will need to be carefully monitored as it gets buried by our next snowfall this weekend. New snow falling on this layer will be more reactive than previous storms where the new snow did not fall on a persistent weak layer. The early February rain crust is another prominent layer in the upper snowpack that requires monitoring, though there have been no recent avalanches on this layer. The lower snowpack is generally well settled and strong.

Terrain and Travel

  • Be alert to conditions that change with elevation, aspect and exposure to wind.
  • Avoid steep, rocky, and wind effected areas where triggering slabs is more likely.
  • Cornice failure may trigger large avalanches.

Avalanche Problems

Wind Slabs

Moderate southerly winds may create small wind slabs that are possible to trigger in steep, convex terrain below ridgetops.

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

Elevations: Alpine.

Likelihood: Possible

Expected Size: 1 - 1.5