Avalog Join
Archived

Avalanche Forecast

Feb 24th, 2020–Feb 25th, 2020
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
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
1: Low
The avalanche danger rating below treeline will be low

Regions: Sea To Sky.

Storm slabs will likely continue to be reactive to human triggers, especially where the wind has loaded deep pockets of snow over a weak interface.

Confidence

High -

Weather Forecast

Monday night: Scattered cloud. Light to moderate northwest wind. Freezing level 600 m.

Tuesday: 5-10 cm new snow. Moderate southwest wind. Freezing level 900 m.

Wednesday: Cloudy. Light to moderate northwest wind. Freezing level 1300 m.

Thursday: Cloudy. Light to moderate northwest wind. Freezing level 1400 m.

Avalanche Summary

Explosive cornice work conducted on Monday produced size 2 results. Skier control work produced size 1-1.5 wind slabs 15-40 cm deep in immediate lees of ridgetops. 

Natural, skier and explosive triggered loose dry and soft slab avalanches to size 1.5 were observed Sunday. Slabs were touchy, 30-60 cm deep and running far on firm bed surfaces.

The deep persistent slab we mistakenly reported yesterday was actually old debris from early February. There have been no reports of avalanches on deep weak layers for several weeks.

Snowpack Summary

30-60 cm of recent snow sits over a layer of widespread surface facets, isolated patched of surface hoar in sheltered areas or sun crusts on solar aspects. In the alpine and exposed treeline, recent snow has been redistributed by strong southwest to northwest wind, loading deep deposits into immediate lee features.

Faceted snow and crusts exist near the base of the snowpack in much of the region. This layer is believed to be largely dormant at the moment but appears to be most likely a problem on the eastern side of the region, in alpine terrain, and where there is relatively smooth ground (e.g., glaciers, scree slopes, rock slabs).

Terrain and Travel

  • Be careful with wind loaded pockets, especially near ridge crests and roll-overs.
  • Recent wind has varied in direction so watch for wind slabs on all aspects.
  • Potential for wide propagation exists, fresh slabs may rest on surface hoar, facets and/or crust.
  • Carefully assess open slopes and convex rolls where buried surface hoar may be preserved.
  • Start on smaller terrain features and gather information before committing to bigger terrain.

Avalanche Problems

Storm Slabs

30-60 cm of recent snow sits over a layer of widespread surface facets, isolated patched of surface hoar in sheltered areas or sun crusts on solar aspects. Storm slabs will be deepest where strong winds have loaded lee terrain features in alpine and exposed treeline areas. Recent winds have varied in direction from south to northwest, wind loading on a variety of aspects.

Aspects: All aspects.

Elevations: All elevations.

Likelihood: Possible - Likely

Expected Size: 1 - 2