Archived

Avalanche Forecast

Feb 21st, 2015–Feb 22nd, 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

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: South Rockies.

Watch for fresh isolated pockets of windslab on reverse loaded features.

Confidence

Good - The weather pattern is stable

Weather Forecast

Were looking at a couple of nice days. Freezing levels will climb during the day but are forecast to return to valley bottom overnight. Sunday will see high of -5C in the Alpine with light westerly winds. Monday will have a high of 0C and light northwesterly winds with increasing clouds in the afternoon. Tuesday will be much the same. No new precipitation is expected through the forecast period.

Avalanche Summary

No new avalanches have been reported recently

Snowpack Summary

Up to 10 cm of new snow may now cover a thick, solid crust that extents up to 2100m and firm wind pressed surface higher than that. The recent winds have been light to moderate from the northeast and I suspect that you may find isolated fresh windslabs forming in reverse loaded lee features on southern aspects. Below 2100m the crust is effectively capping the snowpack and protecting a couple of buried persistent week layers. Two layers of surface hoar can be found between around 50 and 80cm down. Recent snow pack test indicate that these layers are unlikely to fail but could propagate widely if they do. I suspect that at upper elevations where these layers are not protected by the surface crust it could still be possible to trigger an avalanche from a thin or rocky spot. The mid-December crust is becoming harder to find but where it does exist (mainly at treeline elevations) it is over a meter down.

Avalanche Problems

Wind Slabs

Thin, fresh pockets of windslab may be found in reverse loaded lee features.

Be cautious as you transition into wind affected terrain.>Avoid exposure to terrain traps where the consequences of a small avalanche could be serious.>

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

Elevations: Alpine, Treeline.

Likelihood: Unlikely - Possible

Expected Size: 1 - 2

Persistent Slabs

Large avalanches are unlikely in most places but may be possible in the high alpine where a large trigger in a thin rocky spot could cause an avalanche on a buried persistent week layer.

Be alert to conditions that change with elevation, the surface crust that is protecting deeper weak layers tapers out in the high alpine.>Be aware of the potential for very large, deep avalanches due to the presence of buried surface hoar or a facet/crust layer.>

Aspects: All aspects.

Elevations: Alpine.

Likelihood: Unlikely - Possible

Expected Size: 2 - 5