Avalanche Forecast

Issued: Feb 5th, 2018 4:12PM

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

Jasper Snow Safety, Parks Canada

Jasper.

The likelyhood of natural triggering has decreased with cool temps. Preserved weaknesses in the mid snowpack still warrant a cautious approach in some areas, particularly at treeline.

Summary

Weather Forecast

Arctic air will dominate with few clouds, light winds, highs near -10 and lows near -20C. Warm, wet, pacific air is forecast to over-ride the arctic air Wednesday morning. This system may bring up to 25mm of precip with moderate winds and temperatures nearing -5C.

Snowpack Summary

15 cm of new snow arrived last weekend with light N winds. This sits over previous wind slabs formed by 40cm of snow pushed around mainly by strong SW winds. Mid-pack persistent weak layers, mainly preserved Jan 7 surface hoar down 40 to 60cm and the rotten Dec 15 facets sitting just below are still a concern but remain stubborn to triggering.

Avalanche Summary

A good look around today with clear skies. Saw two naturals in the Maligne area in the morning. A few notable avalanches seen through the tenure most of which were at least 48 hrs old; generally windslabs in the alpine to sz 2.5 and a few persistent slabs in the low alpine.

Confidence

Intensity of incoming weather systems is uncertain on Wednesday

Problems

Persistent Slabs

Field teams observed whumpfing and moderate test results Sunday and Monday in sheltered zones around treeline on these layers. Shallow areas seem to be the areas to watch in the alpine.

Use conservative route selection, choose moderate angled and supported terrain with low consequence.

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

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

2 - 3.5

Wind Slabs

10-15cm of new snow that arrived Saturday and Sunday is being redistributed by light to moderate NW winds. This new snow may also be hiding older stiffer windslabs from last weeks heavy snow and strong SW winds.

Be cautious as you transition into wind affected terrain.If triggered the storm/wind slabs may step down to deeper layers resulting in large avalanches.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

1 - 2.5

Loose Dry

The new snow that fell Saturday and Sunday has triggered a few slabs as it has sluffed off of rock faces or steep terrain. Consider the potential for this if you enter steep or confined terrain such as ice climbs.

Avoid terrain traps, such as gullies, where the consequences of a small avalanche could be serious.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

1 - 2

Valid until: Feb 6th, 2018 4:00PM