Archived

Avalanche Forecast

Dec 19th, 2013–Dec 20th, 2013

Alpine

3: Considerable

The avalanche danger rating in the alpine will be considerable

Treeline

3: Considerable

The avalanche danger rating at treeline will be considerable

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

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: Kananaskis.

Wide propagation is the theme of the day. The natural activity has stopped, but be aware that human triggering is still likely in steep, windloaded terrain. TL/ALP transitional terrain deserves attention as the snowpack depth is still variable.

Confidence

Good

Weather Forecast

Winds picking up this evening to the moderate to strong levels at ridge line. Valley bottom winds will be light. Temperatures are expected to remain consistent with today's, a high of -15 in the alpine. No new snow.

Avalanche Summary

A widespread cycle occurred last night and into this morning. For the most part the avalanches were located below cliffs that had continuous spindrift. The spindrift increased the load on the Oct crust, and at the same time it made a slab with enough density to propagate. These avalanches ran far and fast. There were some exceptions. Several avalanches in skiable terrain (sz2) were observed as were numerous loose dry(sz 1) avalanches.

Snowpack Summary

Yesterday's storm snow has settled quickly. 18cm of storm snow as of this afternoon. BTL the trailbreaking is still challenging in untracked areas. At TL and ALP elevations the snowpack is variable in both depth and quality. Any terrain exposed directly to last week's winds is stripped dry with a dusting of storm snow on top. Lee areas are covered with a thick hard slab, which is in turn covered with storm snow. Lots of snow available for wind transport! HS @ Burstall pass: 92cm, HS @ road: 69cm

Avalanche Problems

Wind Slabs

Today's winds were less than expected. Today's expected storm slabs were slow to develop. As the winds pick up the windslab development could quickly change. Steep, immediate lee areas will be suspect as of friday morning.

Avoid freshly wind loaded features.>Avoid areas with overhead hazard.>

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

Elevations: Alpine, Treeline.

Likelihood: Possible - Likely

Expected Size: 1 - 4

Persistent Slabs

This layer isn't done yet. Two concerns here: 1)the crust is an excellent sliding surface for storm slabs, and 2)the crust will be rotten at lower elevations, making deep avalanches a possibility. Assess slopes with these two things in mind.

Be aware of thin areas that may propogate to deeper instabilites.>Be aware of the potential for wide propagations.>

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

Elevations: Alpine, Treeline.

Likelihood: Likely

Expected Size: 2 - 5