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Avalanche Forecast

Feb 1st, 2015–Feb 2nd, 2015
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
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: Purcells.

A technical glitch caused an old bulletin to be published earlier today.  The issue has now been corrected.

Confidence

Fair

Weather Forecast

A series of week fronts will bring up to 10 cm of new snow to the southern interior over Sunday and Monday before a ridge builds Tuesday with a return to dry conditions. Winds should be light from the southwest to west. Freezing levels will remain at valley bottom.

Avalanche Summary

There was a widespread avalanche cycle earlier in the week that produced numerous large to very large avalanches. Natural activity has now eased, but the present of persistent layers in snow pack suggest that it may be possible for humans to trigger an avalanche.

Snowpack Summary

A melt-freeze crust exists up to around 2200 m, overlying moist snow. At higher elevations, the surface is heavily wind affected. The depth of the mid-January surface hoar is highly variable across the region and it may have been destroyed by warmth at low elevations. Where it does exist, it can be found between 20 and 70 cm below the surface. The mid-December surface hoar layer lies below a strong mid-pack down about 60 to 120cm. Both of these persistent layers have been reactive recently. The mid-November weak layer of crusts and facets can still be found near the bottom of the snowpack. It has been unreactive lately, but should be on your radar in shallow snowpack areas where there may sill be a chance of triggering it.

Avalanche Problems

Persistent Slabs

A layer of surface hoar buried in the upper snowpack remains a concern.
Choose well supported terrain without convexities.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Possible

Expected Size: 2 - 5

Deep Persistent Slabs

Deeply buried weak layers may react to large loads like a cornice collapse, or could be triggered by light loads in thin/ variable snowpack areas.
Pay attention to overhead hazards like cornices.>Stay clear of thin areas that may propagate to deeper instabilities.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Unlikely - Possible

Expected Size: 3 - 6