Avalanche Forecast

Issued: Jan 2nd, 2020 4:00PM

The alpine rating is high, the treeline rating is high, and the below treeline rating is considerable. Known problems include Storm Slabs, Deep Persistent Slabs and Loose Dry.

Jasper Snow Safety, Parks Canada

Jasper.

The start of another storm is due to hit us this evening. Strong to extreme Southwest winds accompanied by 25-40cm will test the snowpack.

Summary

Weather Forecast

Tonight: Cloudy with scattered flurries. Precipitation: 5 cm. Alpine temperature: Low -17 C. southwest: 15 km/h.

Friday: 12cm, warming to -5 and accompanied by moderate SW winds gusting to 100km!

Sat & Sun 26cm expected with Moderate SW winds gusting to 70km.

Visit CAA's Mountain Weather Forecast for more specific details.

Snowpack Summary

An additional 9cm last night in the parkers area. Variable amounts of snowfall through the region, burying large surface hoar, present up to 2200m in sheltered areas. SW winds continue to created new wind slabs on lee features at treeline and above. The bottom of the snowpack consists of very pronounced facets, decomposing crusts and depth hoar.

Avalanche Summary

Several avalanches observed today on west aspects to size 2.5

Concerning results from snowpack tests in Southern forecast region around Mount Wilson. Moderate to hard sudden planar results at treeline on the weak basal depth hoar/facet layers.

Confidence

Intensity of incoming weather systems is uncertain

Problems

Storm Slabs

An avalanche initiated in this storm snow may step down and test our deeper weak layers

If triggered the storm slabs may step down to deeper layers resulting in large avalanches.
Use caution in lee areas. Recent snowfall mixed with wind loading has created storm slabs.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Very Likely

Expected Size

1 - 2

Deep Persistent Slabs

This weakness could be triggered by large loads or from thin spots in the snowpack. This problem seems more pronounced at treeline where whumphing and cracks have been observed.

Be aware of thin areas that may propogate to deeper instabilites.
Watch for whumpfing, hollow sounds, and shooting cracks.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

1 - 3

Loose Dry

10-20cm new expected in the next pulse of the storm. Caution in steep gullies and terrain traps where a small sluff could have large consequences.

Watch for terrain traps where small amounts of snow will acumulate into deep deposits.

Aspects: All aspects.

Elevations: Treeline, Below Treeline.

Likelihood

Likely - Very Likely

Expected Size

1 - 2

Valid until: Jan 3rd, 2020 4:00PM