Avalanche Forecast

Issued: Feb 12th, 2014 4:00PM

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

garth lemke, Parks Canada

Jasper.

We received variable amounts from 2-15cm with winds coming from all directions. Does not seem like allot but wind loading can quickly triple the depth. Give the storm snow a few days to heal. Won't take long with warm temperatures.

Summary

Weather Forecast

Unsettled weather until Saturday. Expect 5-10cm on Thursday with another 5-10cm on Friday accompanied by light to gusting moderate ridgetop SW winds. Freezing levels will hover around 1000m with slight warming trend Friday and clearing skies on Saturday potentially spiking the temperature on solar aspects.

Snowpack Summary

A storm brought 10-15cm. It overlies a potential sliding layer 20cm down of surface facets/surface hoar. Variable wind directions are developing slabs on all aspects but pay particular attention to NE aspects where loading patterns could triple the slab thickness. A hard mid-pack is bridging weak basal facets at tree line and above.

Avalanche Summary

No new avalanches reported but visibility was minimal. Expecting some direct action storm snow avalanches in the alpine from this new snow plus what's going to accumulate and windload over the next few days.

Confidence

Forecast snowfall amounts are uncertain on Thursday

Problems

Deep Persistent Slabs

Bridging above this layer makes it stubborn to initiate; however, it will be big when it goes. A sudden warming, large additional snowload, large triggers, or surface avalanches may tip the scale. Be aware of thin locations as likely trigger spots.

Carefully evaluate and use caution around thin snowpack areas.Assess start zones carefully and use safe travel techniques.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Unlikely - Possible

Expected Size

2 - 4

Storm Slabs

15cm of new snow with variable wind directions and speeds have translated to wind loaded pockets of storm slab potentially 45cm thick overlying weak surface facets. More snow Thurs-Fri will add to this condition. Loose avalanches are also possible.

Watch for terrain traps where small amounts of snow will acumulate into deep deposits.Avoid freshly wind loaded features.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

1 - 3

Valid until: Feb 13th, 2014 4:00PM