Avalanche Forecast

Issued: Jan 3rd, 2019 4:00PM

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

Timothy Johnson, Parks Canada

Jasper.

Exceptional amounts of snow is falling over the Bulletin Region. Avoid all Avalanche Terrain.

Summary

Weather Forecast

An ongoing storm is bringing heavy snowfall and strong winds to our area. Up to 45cm of snow has already fallen and 25cm more snow with moderate to strong winds are still forecast through Friday. Temperatures will stay warm around -5C to -8C. A detailed mountain weather forecast is available from Avalanche Canada.

Snowpack Summary

Up to 45cm of snow has fallen along the 93N. Moderate-strong SW winds have built fresh windslabs in open terrain and storm slabs in sheltered areas. Expect natural avalanche activity with the rapid loading. The Dec. 11th layer (surface hoar and facets) persists down 60-150cm, and continues to produce avalanches in shallow snowpack areas.

Avalanche Summary

Upper avalanche start zones were obscured with falling snow but we expect widespread natural avalanche activity to be occurring. Yesterday skier triggered and several natural slabs were noted on slopes with shallower snowpack around the Columbia Icefields.

Confidence

Forecast snowfall amounts are uncertain on Friday

Problems

Wind Slabs

Up to 45cm of fresh snow, warm temperatures and moderate to strong SW winds are creating widespread touchy windslabs and storm slabs.

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

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Very Likely

Expected Size

1 - 3

Persistent Slabs

The new snow has added to the load on the Dec 11th weak interface. Buried more than a meter deep in some locations, this layer is strengthening but has been reactive in shallow snowpack areas recently.

Avoid avalanche terrain during periods of heavy loading from new snow, wind, or rain.Pay attention to overhead hazards like cornices which could trigger the deep persistent slab.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely - Very Likely

Expected Size

1.5 - 3.5

Deep Persistent Slabs

The base of the snowpack is weak and facetted. In shallow snowpack areas the new snow will likely overload this weakness.

Avoid thin, rocky or unsupported slopes.Avoid exposure to overhead avalanche terrain, large avalanches may reach the end of run out zones.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1.5 - 4

Valid until: Jan 4th, 2019 4:00PM