Avalanche Forecast

Issued: Jan 10th, 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, Deep Persistent Slabs and Persistent Slabs.

jasper snow safety, Parks Canada

Jasper.

Watch out for building wind slabs and cornices.

Summary

Weather Forecast

Friday will be cloudy, no precipitation, Alpine High -7 C, and ridge wind southwest 15 km/h. Saturday will be sun, Alpine temperature low -3 C high -1 C, wind southwest 10 km/h, and freezing level 1900 metres. Temperatures may be warmer than forecasted on Saturday. A detailed mountain weather forecast is available from Avalanche Canada.

Snowpack Summary

Moderate to strong winds and allot of snow available for transport from Jan 2-4th 85cm storm continues to build ridge top wind slabs. Last week's snow is settling into a cohesive layer and is overlying; previous widespread wind effect; the Dec. 11th layer in the mid-snowpack; and a weak facet layer on the ground (particularly weak where shallow).

Avalanche Summary

No new naturals observed on Thursday and visibility was good. To the South of Saskatchewan crossing there continues to be consistent reports of large avalanches. Jan 5th helicopter control produced numerous large avalanches with one on Sunset peak destroying 14 hectares of mature timber.

Confidence

Freezing levels are uncertain on Saturday

Problems

Wind Slabs

Moderate - strong W winds, snow available for transport, and warming temps continue to add to the wind slab problem.

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: North, North East, East, South East, North West.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2.5

Deep Persistent Slabs

The base of the snowpack is weak and facetted in shallow areas and will likely be for some time. The Jan 2-4th 85cm of new snow in combination with a skier has the potential to overload this weakness.

Pay attention to overhead hazards like cornices which could easily trigger the deep persistent slab.Avoid steep convexities or areas with a thin or variable snowpack.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

1.5 - 4

Persistent Slabs

The Dec. 11th layer of facets and surface hoar is buried more than a meter deep. This layer is strengthening but was active during the recent storm.

Be aware of the potential for wide propagations.Dig down to find and test weak layers before committing to a line.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1.5 - 3.5

Valid until: Jan 11th, 2019 4:00PM