Avalanche Forecast

Issued: Jan 6th, 2019 4:00PM

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

jasper snow safety, Parks Canada

Jasper.

The storm snow is starting to settle in yet its still too early to be bold in the terrain. Use caution as localized slab development and analysis will be critically important for safe travel in the back-country.

Summary

Weather Forecast

Monday will be a mix of sun and cloud with isolated flurries, trace of snow, alpine high -13 °C, and ridge wind west at 20 km/h gusting to 45 km/h. Tuesday will be mix of sun and cloud, no precipitation, -21 °C to -12 °C, and wind southwest 20 km/h. A detailed mountain weather forecast is available from Avalanche Canada.

Snowpack Summary

Jan 2-4, up to 45cm of snow arrived along the 93N. Moderate-strong SW winds built fresh wind slabs in open terrain. The Dec. 11th layer (surface hoar and facets) persists down 60-150cm, and continues to produce avalanches in shallow snowpack areas.

Avalanche Summary

Jan 5th helicopter control on high and low targets produced numerous avalanches with one being a size 4 at Sunset Pass; burying the Icefields Parkway with significant debris and mature trees.

Confidence

Problems

Wind Slabs

Up to 45cm of new snow from Jan 2-4th, warm temperatures and moderate to strong SW winds created windslabs.

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

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 3

Persistent Slabs

The new snow has added to the load on the Dec 11th interface. It is buried more than a meter deep in some locations. This layer is strengthening but was active during the storm in shallow snowpack areas.

Pay attention to overhead hazards like cornices which could trigger the deep persistent slab.Avoid shallow snowpack areas where triggering is more likely.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

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 in combination with a skier has the potential to overload this weakness.

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

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1.5 - 4

Valid until: Jan 7th, 2019 4:00PM