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Archived

Avalanche Forecast

Dec 19th, 2018–Dec 19th, 2018
Alpine
4: High
The avalanche danger rating in the alpine will be high
Treeline
3: Considerable
The avalanche danger rating at treeline will be considerable
Below Treeline
3: Considerable
The avalanche danger rating below treeline will be considerable
Alpine
4: High
The avalanche danger rating in the alpine will be high
Treeline
4: High
The avalanche danger rating at treeline will be high
Below Treeline
4: High
The avalanche danger rating below treeline will be high
Alpine
4: High
The avalanche danger rating in the alpine will be high
Treeline
4: High
The avalanche danger rating at treeline will be high
Below Treeline
4: High
The avalanche danger rating below treeline will be high

Regions: Jasper.

More forecast snow and strong winds will increase the avalanche danger into the weekend.Avalanche control is planned between Parkers Ridge and Sask. Crossing on Wednesday Dec. 19th. Expect intermittent closures.

Weather Forecast

Stormy weather is expected into the weekend as a series of coastal lows bring moisture over the region. The weather models don't agree but 35cm of snowfall could fall between Wednesday and Friday evening with gusting strong westerly winds. A detailed mountain weather forecast is available from Avalanche Canada.

Snowpack Summary

Up to 30 cm of new snow has been blown into fresh wind slabs by moderate SW winds. The December 11th persistent weak layer (facets, crusts and isolated surface hoar) has been buried by up to 80cm of fallen snow - this has been loaded into lee terrain by moderate to strong SW wind. The deep persistent weakness still lingers near the ground.

Avalanche Summary

A lack of visibility is hiding any new avalanches but on Tuesday a field team at Parkers Ridge observed many signs of instability (shooting cracks and whumphs) and spooky sudden result in snow pits. Last week, a natural avalanche cycle and subsequent avalanche control work resulted in many slab avalanches up to size 3.5 in the Parkers ridge area.

Confidence

Timing, track, or intensity of incoming weather system is uncertain.

Avalanche Problems

Persistent Slabs

Determining the strength of bond at the Dec11th interface is key to safe travel in avalanche terrain.
Minimize overhead exposure during periods of heavy loading from new snow, wind.Watch for signs of instability such as whumpfing, or cracking.

Aspects: All aspects.

Elevations: All elevations.

Likelihood: Likely

Expected Size: 1.5 - 3.5

Wind Slabs

Moderate SW winds have built windslabs particularly at ridge-tops. These are sensitive in the loading zones, most notably NE exposed treeline and alpine features.
If triggered the wind slabs may step down to deeper layers resulting in large avalanches.Use caution in lee areas. Recent wind loading has created wind slabs.

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

Elevations: Alpine, Treeline.

Likelihood: Likely

Expected Size: 1 - 2.5

Deep Persistent Slabs

Several recent large avalanches have been the result of the entire snowpack failing on or near the ground due to the weak snowpack structure surrounding this interface.
If triggered the wind slabs may step down to deeper layers resulting in large avalanches.Be aware of the potential for wide propagations.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Possible

Expected Size: 1.5 - 3.5