Avalanche Forecast

Issued: Feb 18th, 2017 4:00PM

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

mark herbison, Parks Canada

Jasper.

http://www.pc.gc.ca/apps/links/goto_e.asp?destination=Special Public Avalanche Warning has been issued for Jasper National Park due to dangerous avalanche conditions. "The snowpack is touchy and even though it looks enticing, it is unforgiving right now" - CS

Summary

Weather Forecast

Light flurries over the next few days will accumulate up to 15cm of new snow. Temps to remain between -3 to -10 in the Alpine with light (1-25km/hr) SW winds. Freezing levels could go as high as 1600m on Sunday.

Snowpack Summary

25cm HST in the past 4 days along the Columbia Icefields and 35km/hr SW winds have built, yet another, layer of windslab TL and ALP. A rain crust (up to 20cm) exists below 1900m. The denser upper snowpack overlies a weak faceted lower pack, making for very tricky and dangerous avalanche conditions .

Avalanche Summary

A sz 3 slab released from a steep rocky area below ridgeline from Churchill South, NE aspect, 2500m elevation. Crown was ~100cm deep, 200m wide and traveled into the runout zone. A sz 2 released in a steep gully at treeline on Mt. Wilson today, dusting the highway.Widespread whumphing and shooting cracks were noted on all elevations.

Confidence

Due to the number of field observations on Saturday

Problems

Deep Persistent Slabs

Widespread whumphing and shooting cracks in previously un-skied terrain. Recent natural activity up to Sz 3 failing on the weak faceted snowpack.

Watch for shooting cracks or stiffer feeling snow. Avoid areas that appear wind loaded.Be aware of thin areas that may propogate to deeper instabilites.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 3

Wind Slabs

25cm HST and moderate SW winds have added to the windslab problem in the alpine and open tree-line features.

Be aware of the potential for wide propagations due to the presence of hard windslabs.Use caution in lee areas. Recent wind loading have created wind slabs.

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 3

Valid until: Feb 19th, 2017 4:00PM