Avalanche Forecast

Issued: Jan 12th, 2014 7:18AM

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

Alberta Parks mike.koppang, Alberta Parks

Natural avalanche activity is decreasing right now but many slopes are simply waiting for a trigger.  Use caution, be conservative and dont be that trigger.

Summary

Confidence

Good

Weather Forecast

Another system is expected to cross the region on Sunday night giving us another 15cm of new snow but...strong to extreme SW winds.  This new snow will add additional load to the previous windslabs trhat have been developing over the past 36hrs.  Temps are supposed to warm up on Monday to -10C in Alpine terrain.  The storm will likely blow through by mid day on monday giving us generally grey skies for the majority of the day.

Avalanche Summary

There was lots of evidence of previous avalanche activity but many of the fracture lines were already blow in.  There were a few sz 1.5s off of a SE aspect on Mt Sparrowhawk around 2600m and a large sz 3 noteable on Mt Nestor.  The Nestor slide was up to 500m wide, 30-80cm deep and ran full path over 1000m to the end of its historical runout.  The natural avalanche cycles seems to be coming to an end but many slope are simply waiting for a trigger.  Dont be that trigger.

Snowpack Summary

Storm snow totals were around 30-40cm of snow but the strong to extreme SW winds have redistributed most available snow onto lee features and stripped many of the windward slopes down to minimal or no snow cover.  The new windslabs are sitting on a mixture of low density storm snow or the previous windslabs that had developed earlier in the week.  Lots of whumpfing was being experienced as forecasters approached more open terrain indicating the current snowpack is unstable.  The weak basal facets are still a large concern for us knowing that any avalanche that initiates it likely to involve the entire winters snowpack.  Thin weak are are plentiful but you should use great caution to avoid these areas.  Steeper terrain will not be the place to be likely until spring, sorry...

Problems

Wind Slabs

An icon showing Wind Slabs
Widespread skier triggerable windslabs can now be found in Alpine and treeline areas.  These slabs are sensitive to light loads such as a skier so use caution as you transition into more wind affected areas.
Be cautious as you transition into wind affected terrain.>Avoid all avalanche terrain during periods of heavy loading from new snow, wind, or rain.>

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

2 - 5

Persistent Slabs

An icon showing Persistent Slabs
There were a few avalanches that failed full depth in the recent storm.  Be aware, any avalanche that initiates is likely to involve the entire winters snowpack.
Be aware of the potential for full depth avalanches due to deeply buried weak layers.>Avoid exposure to overhead avalanche terrain, large avalanches may reach the end of run out zones.>

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

3 - 6

Valid until: Jan 13th, 2014 2:00PM

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