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Avalanche Forecast

Feb 9th, 2020–Feb 10th, 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
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
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: Lizard-Flathead.

Natural avalanche activity has likely slowed, but human triggered storm slab avalanches remain possible, especially on features immediately lee of ridge crest. If you are increasing your exposure to avalanche terrain, do it gradually as you gather information.

Confidence

Moderate - Uncertainty is due to how quickly the snowpack will recover and gain strength.

Weather Forecast

Aside from a few bouts of potentially strong wind, we’re moving into a rather benign weather pattern for the foreseeable future.

SUNDAY NIGHT: Freezing level at valley bottom, light to moderate northwest wind, no significant precipitation expected.

MONDAY: A few clouds, freezing level rising to 800 m in the afternoon, light wind generally out of the northwest, no significant precipitation expected.

TUESDAY: Scattered cloud cover, freezing level rising to around 1300 m in the afternoon, moderate to strong northwest wind, trace of precipitation possible.

WEDNESDAY: Scattered cloud cover, freezing level near valley bottom, light variable wind, trace of precipitation possible.

Avalanche Summary

On Saturday storm slab avalanches to size 2 were widespread. They ran naturally and were intentionally triggered by avalanche control work on all aspects.  

Fragile cornices and one large cornice fall have been reported over the past week.

Snowpack Summary

The weekend storm produced 15 to 25 cm of warm storm snow. This snow has been formed into slabs in wind exposed terrain by previously strong winds that were largely out of the northeast. This snow rests on previously wind affected snow and a thick rain crust that exists up to roughly 2100 m. In many areas this capping crust extends to mountaintops. Sheltered areas now have 15-30 cm of snow above the crust. The bottom 20 cm of the snowpack consists of basal facets and decomposing crusts that have not been an active avalanche problem since December, but could reemerge as a problem after sustained warming.

Terrain and Travel

  • Be especially cautious as you transition into wind affected terrain.
  • Don't be too cavalier with decision making, storm slabs may remain sensitive to human triggering.
  • Start with conservative lines and watch for clues of instability.

Avalanche Problems

Storm Slabs

Storm slabs have formed above a widespread crust, Natural activity has likely slowed down, but human triggering remains possible. Potentially deep wind-fueled storm slabs can likely be found near ridge crest.

Aspects: All aspects.

Elevations: All elevations.

Likelihood: Possible

Expected Size: 1 - 2.5