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Avalanche Forecast

Feb 9th, 2019–Feb 10th, 2019
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
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
1: Low
The avalanche danger rating at treeline will be low
Below Treeline
1: Low
The avalanche danger rating below treeline will be low

Regions: Sea To Sky.

Stiff wind slabs may be reactive to human triggers at upper elevations. Steep, unsupported rolls and immediate lee terrain is most suspect.

Confidence

Moderate - Wind effect is extremely variable

Weather Forecast

SATURDAY NIGHT: Clear and starry. Alpine temperatures near -18C. Ridgetop winds strong decreasing to moderate from the northeast.SUNDAY: Mix of sun and cloud with possible isolated flurries, trace accumulation. Alpine temperatures near -13C. Ridgetop winds light to moderate from the northeast.MONDAY: Sunny with cloudy periods. Alpine temperatures near -15C. Ridgetop winds light to moderate from the east.TUESDAY: Mix of sun and cloud with isolated flurries, trace accumulation. Alpine temperature near -16C. Ridgetop winds moderate from the northeast.

Avalanche Summary

Pockets of wind slab were reactive to skier traffic early this week, resulting in avalanches up to size 2 in the alpine. Recent reactivity of wind slabs has been confined to steep, unsupported rolls.

Snowpack Summary

Significant strong to extreme winds have redistributed the 40-50 cm of recent snow in the alpine and treeline, producing a variety of wind affected surfaces including hard/soft wind slabs, sastrugi, and isolated and protected pockets of soft faceted snow. Expect wind affect to extend to all elevations including a surface wind skin at lower elevations.Due to scouring and wind-loading, anywhere from 0-60 cm recent snow sits on a crust on all aspects below 2000m and solar aspects into the alpine. In isolated and sheltered terrain at treeline and below, a layer of weak feathery surface hoar or sugary facets may be identified, but with little reactivity. Current cold temperatures are promoting surface faceting and are breaking down the buried crust.The remainder of the snowpack is generally well-settled.

Avalanche Problems

Wind Slabs

Shifting winds and strong outflows have formed stiff pockets of wind slab in wind-loaded terrain. The most reactive wind slabs will be found in steep, unsupported terrain and immediate lee features.
Be careful with wind loaded pockets, especially near ridge crests and roll-overs.Be cautious as you transition into wind affected terrain.Watch for whumpfing, hollow sounds, and shooting cracks.

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

Elevations: Alpine, Treeline.

Likelihood: Possible

Expected Size: 1 - 2