Avalanche Forecast

Issued: Nov 24th, 2017 3:06PM

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

Alberta Parks KESAdmin, Alberta Parks

Cooler temps are tightening up the snowpack but it will still take a bit of time to settle.  Another storm is forecast to cross the region on Sunday/Monday.

Summary

Confidence

Moderate - Timing of incoming weather systems is uncertain on Sunday

Weather Forecast

Saturday should be a carbon copy of friday in terms of weather.  Mainly cloudy, moderate westerly winds and light flurries with only minor accumulations.  On Sunday another storm is forecast to hit the region.  At this time precipitation amounts are close to 25cm with strong winds and again warm temperatures.  We can expect the avalanche danger to increase if the forecast holds true.

Avalanche Summary

A few recent avalanches up to sz 2.5 were observed initiating in Alpine areas on N and E aspects.  These slides started as dry windslabs, then ran down into the rain soaked snow and ran to the top of their normal runouts.  The majority of avalanches observed were 30-40cm thick, 60-100m wide and ran 200-300m. 

Snowpack Summary

Cooler temperatures moved in overnight and we finally saw the rain begin to turn to snow.  Below 2200m the snowpack was rain soaked, lost lots of mass but it now beginning to re-freeze.  Above this elevation the top 5-20cm of the snowpack was moist and isothermal.  So far it seems as if 2600m was a high as the rain fell and it was snow above.  So, we now have what is being called the November rain crust buried down 10-15cm up to 2600m.  Above this elevation the new snow and winds have combined to build new windslabs in open areas.  These new windslabs will be reactive to a skiers weight so avoid steeper areas until the snowpack has some time to settle and strengthen. 

Problems

Persistent Slabs

An icon showing Persistent Slabs
Recent avalanche activity has occurred on the halloween layer down 30-60cm.  Dig down and check this interface.
Watch for areas of hard wind slab in steep alpine features.Be careful with wind loaded pockets. Be aware of wide variation in snowpack depthBe aware of the potential for wide propagations.

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 3

Wind Slabs

An icon showing Wind Slabs
New windslabs building in Alpine areas and isolated areas at treeline as a result of strong westerly winds.
Use caution in lee areas. Recent wind loading has created wind slabs.

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2

Valid until: Nov 25th, 2017 2:00PM

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