Avalanche Forecast

Archived

Dec 18th, 2022–Dec 19th, 2022

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely.

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely.

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely.

Regions

Jasper, Brazeau, Churchill, Cirrus-Wilson, Fryatt, Icefields, Maligne, Marmot, Miette Lake, Pyramid.

Extreme cold temperatures for the next few days - keep this in mind as any incident or equipment failure may lead to severe consequences.

We have switched Jasper's main avalanche problem from a persistent slab to a deep persistent slab. The persistent slab has not gone away but any avalanche triggered in the upper snowpack will likely step down to weak facet crystals on or near the ground resulting in large avalanches.

Confidence

Moderate

Avalanche Summary

No new avalanches have been observed or reported on the icefields parkway. On December 14th in the Parker Ridge/Mt. Saskatchewan area, a couple of natural avalanches to size 2 were reported stepping down to ground in the alpine.

Snowpack Summary

2-5 cm of snow fell on December 17th and has buried a surface hoar / facet layer in sheltered areas at tree line and below. In the alpine, surface conditions are variable with a mix of hard wind pressed snow and facets. A persistent weak layer is down 25-35cm specific to tree line and below in sheltered areas. The bottom of the snowpack is weak consisting of basal facets with pockets of depth hoar. The snowpack height ranges from 40-100cm. Snowpack is unsupportive tree line and below.

Weather Summary

An Arctic ridge will bring extreme cold temperatures and dry conditions through the week. Winds will be light from the northeast. No significant precipitation is expected during the forecast period.

Terrain and Travel Advice

Uncertainty is best managed through conservative terrain choices at this time.

Problems

Deep Persistent Slabs

Deep Persistent Slab avalanches are the release of a thick cohesive layer of hard snow (a slab), when the bond breaks between the slab and an underlying persistent weak layer deep in the snowpack. The most common persistent weak layers involved in deep, persistent slabs are depth hoar or facets surrounding a deeply buried crust. Deep Persistent Slabs are typically hard to trigger, are very destructive and dangerous due to the large mass of snow involved, and can persist for months once developed. They are often triggered from areas where the snow is shallow and weak, and are particularly difficult to forecast for and manage.

Loose Dry

Loose Dry avalanches are the release of dry unconsolidated snow and typically occur within layers of soft snow near the surface of the snowpack. These avalanches start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. Other names for loose-dry avalanches include point-release avalanches or sluffs.