Avalanche Forecast

Issued: Jan 11th, 2014 3:00PM

The alpine rating is high, the treeline rating is high, and the below treeline rating is considerable. Known problems include Storm Slabs, Persistent Slabs and Wind Slabs.

mike.koppang, Alberta Parks

Kananaskis.

40cm of new storm snow combined with strong SW winds and warm temps create perfect conditions to make slabs and cause poor stability. Large avalanches involving the entire winter snowpack are occurring. Terrain recognition and avoidance are key!

Summary

Confidence

Fair - Due to the number of field observations on Saturday

Weather Forecast

An unstable air mass over us will continue to dominate the weather over the next few days. On Sunday, winds and temps will decrease a little but we should still expect to see moderate SW winds throughout the day at treeline and above. Forecasts are calling for an additional 8-10cm overnight, then dribs and drabs throughout the day on Sunday. On Monday another pulse is expected to cross the region giving us another 10-15cm but the confidence in this system and the precip amounts are uncertain.

Avalanche Summary

Visibility was obscured throughout most of the day on Saturday and as a result, avalanche observations were limited. Forecasting staff were able to ski cut two sz 1.5 slabs within the storm snow on a steep N aspect at treeline. These slabs did not step down to the weak basal layers but this was in previously skied terrain.

Snowpack Summary

Up to 40cm recent storm snow has fallen over a variety of different snow surfaces. This snow fell under mild temperatures (-4C) and strong to extreme winds at all elevations. As a result, new storm slabs have been quick to develop and have been rapidly overloading the weak basal facets that exist throughout the region. Cracking along ridgelines and below ridgecrests was observed which is a good indicator of poor stability within the snowpack. Warm temps will allow these new avalanche problems to settle out quickly but for the time being, we are in a period of poor stability.

Problems

Storm Slabs

Touchy storm slabs are developing in Alpine and at treeline throughout the region. These slabs are up to 50cm thick and are reactive to light loads such as a skier.

Good day to make conservative terrain choices.>Stick to non-avalanche terrain or small features with limited consequence.>Avoid all avalanche terrain during periods of heavy loading from new snow, wind, or rain.>

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

Elevations: Alpine, Treeline.

Likelihood

Very Likely

Expected Size

2 - 4

Persistent Slabs

The new snow is adding more load to the basal facets and in some areas overloading them triggerring an avalanche that is involving the entire winters snowpack. Be conscious of large avalanches.

Avoid exposure to overhead avalanche terrain, large avalanches may reach the end of run out zones.>Be aware of the potential for full depth avalanches due to deeply buried weak layers.>

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

3 - 6

Wind Slabs

Wind slabs are now buried underneath the recent storm snow. These slabs had been settling but the new load from the recent snow may be enough to wake up these problems.

Avoid all avalanche terrain during periods of heavy loading from new snow, wind, or rain.>Be cautious as you transition into wind affected terrain.>

Aspects: North, North East, East.

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

2 - 4

Valid until: Jan 12th, 2014 2:00PM