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Archived

Avalanche Forecast

Feb 16th, 2021–Feb 17th, 2021
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
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
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

Regions: Glacier.

The faceted upper snowpack is weaker than the normal conditions we enjoy at Rogers Pass. With continuing cold weather, it will not heal as quickly as one would like.

Have patience. Eventually it will warm up and dump once again.

Weather Forecast

Unsettled grey days with hints of sun and a trace of snow.

Today: Cloudy with sunny periods, Alp high -11*C, light/mod W ridge winds

Wed: Sun and cloud, Alp high -15*C, mod W winds

Thurs: Cloud and sun, Alp high -13*C, mod S winds

Fri: Cloudy, scattered flurries, 5cm, Alp high -10*C, mod S winds

Snowpack Summary

Widespread wind effect in the alpine has made for tricky travel. Large lenses of dense, hard slab are mixed with cold, cream cheese powder. The cold has weakened cornices and the upper snowpack. The January 24th weak interface, down 70-100cm, is faceting and weakening in the cold. The mid-lower snowpack is still relatively strong.

Avalanche Summary

Large natural avalanches to sz 3 were observed from the N side of Macdonald yesterday. Mac 6 ran sz 3, Mac 8, 9, 10, 11 all sz 2-2.5

Old but relevant news: a group of skiers had a close call Wed on the S face of Corbin Peak, triggering a sz 2 and a sz 3 on the Jan 24th persistent weak layer. This problem still lurks on big alpine faces.

Confidence

Avalanche Problems

Wind Slabs

Variable mod-strong winds have changed the usual wind-loading pattern across various drainages. Look for signs of the recent local wind direction. Features like gullies, bowls, ribs, etc can be cross-loaded where terrain has multiple aspects.

  • Watch for reverse loading created by N-NE winds.
  • Watch for pockets of hard windslab in steep alpine features.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Possible

Expected Size: 1 - 3

Persistent Slabs

The January 24th weak interface may be triggerable on solar aspects, where facets and/or surface hoar are sitting on a suncrust.

The bond at this interface may be weakening with facets having grown under recent cold temperatures.

  • Dig down to find and test weak layers before committing to a line.
  • Persistent slabs may be more sensitive to human triggering on solar asp where it sits on sun crust

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

Elevations: Alpine, Treeline.

Likelihood: Unlikely - Possible

Expected Size: 1.5 - 3