Avalanche Forecast

Issued: Mar 31st, 2016 3:00PM

The alpine rating is high, the treeline rating is high, and the below treeline rating is moderate. Known problems include Deep Persistent Slabs, Loose Wet and Cornices.

Alberta Parks mike.koppang, Alberta Parks

Solar radiation and a poor overnight freeze will likely contribute to large avalanche on Friday.  If it hasn't slid yet, it may tomorrow resulting in a large avalanche.  If you go out, be out and back early while its still cold and avoid big terrain.

Summary

Confidence

Moderate - Timing or intensity of solar radiation is uncertain on Friday

Weather Forecast

Weather on Thursday night is calling for mainly cloudy and then on friday, the sun is expected to come out...  This means we will only have a minimal freeze likely overnight and strong solar radiation on Friday.  No new snow is forecast and freezing levels will be around 2300m.

Avalanche Summary

A few loose wet slides were observed early in the day.  When the sun came out we had reports of sz 2 and 3 avalanches almost within a few min's of its affect being noticed.  These occurred mainly on solar aspects.

Snowpack Summary

The clouds held the heat in all day and temps at 2200m reached almost +10C.  The upper snowpack is rapidly settling and becomming isothermal in some areas (lower elevations).  The rapid settling is beginning to overload some of the basal interfaces and triggerring what will likely be the climax avalanche cycle of the season.  We should expect paths that have not yet slid to now start to release as large destructive avalanches.  These avalanches are/will likely fail on the weak basal layers down near the ground.  The sun is having a large impact on stability in terms of when it comes out, the solar radiation rapidly decreases the stability and natural avalancehs occur.  If you wanna start really early you may be able to hang onto the crusts for a few hours but start really early....  And be home early also...

Problems

Deep Persistent Slabs

An icon showing Deep Persistent Slabs
The current snowpack structure of dense mid-pack overlying as much as 80cm of weak facets is a recipe for full depth avalanches. Triggering from shallow snowpack areas is a particular concern.  Warm temps also seem to awakening these basal layers.
Be aware of the potential for full depth avalanches due to deeply buried weak layers.>Avoid exposure to solar aspects overhead, large avalanches may reach the end of run out zones.>Avoid convexities or areas with a thin or variable snowpack.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

3 - 6

Loose Wet

An icon showing Loose Wet
Loose wet slides are occurring on steeper solar aspects.  A loose wet slide may grow to a size big enough to trigger a slab on the underlying slopes.
Avoid sun exposed slopes when the solar radiation is strong, especially if snow is moist or wet.>Watch for clues, like sluffing off of cliffs, that the snowpack is warming up. >

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

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

1 - 3

Cornices

An icon showing Cornices
Cornices will likely fail at an increased rate with the influx of heat.  These massive loads are likely to trigger slabs on underlying slopes.
Cornices become weak with daytime heating. >Do not travel on slopes that are exposed to cornices overhead.>Avoid steep slopes below cornices.>

Aspects: All aspects.

Elevations: Alpine.

Likelihood

Possible - Likely

Expected Size

2 - 5

Valid until: Apr 1st, 2016 2:00PM

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