Archived

Avalanche Forecast

Feb 21st, 2013–Feb 22nd, 2013

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

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: Jasper.

Some storm snow and winds are expected Friday into Saturday. Monitor loading patterns after the storm as surface instabilities will exist until the snow has stabilized.

Weather Forecast

A warm front followed by a cold front may pass through Friday into Saturday. Severe SW winds at 3000m and 50km/hr winds at 1500m may be here Friday am followed by 15cm of snow starting late Friday afternoon into Saturday am. Saturday and Sunday, winds will settle, temperatures will be seasonal, light flurries, and variable clouds.

Snowpack Summary

Variable windslabs exist in the alpine and treeline locations. They are bonding well to the previous surfaces. Many spots have been stripped of Saturday's storm snow revealing previous sustrugi and windslab surfaces with windpressed pockets in between. Weak facets dominate low elevations. Solid midpack bridges basal facets treeline and alpine.

Avalanche Summary

Thursday's patrol into Portal creek from Marmot basin revealed no new avalanches. No Patrol on Wednesday. Tuesday observed only a couple size 1.5 very steep loose avalanches @ 2600m appearing to be solar triggered. One size 2 thin slab was noted at 2700m E aspect on a very steep unsupported feature. They appear to be stopping where angle changes.

Confidence

Timing, track, or intensity of incoming weather system is uncertain on Friday

Avalanche Problems

Wind Slabs

Saturday's 20cm of snow has evolved into a variable windslab and appears to be bonding well. It sits on a variety of surfaces such as previously hard slab and sastrugi.

Make observations and assess conditions continually as you travel.Assess start zones carefully and use safe travel techniques.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Unlikely - Possible

Expected Size: 1 - 3