Avalanche Forecast

Archived

Mar 14th, 2023–Mar 15th, 2023

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches possible, human triggered probable.

Below Treeline

Natural avalanches unlikely.

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely.

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely, human triggered possible.

Regions

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

The new snow has made for good riding conditions in sheltered terrain. Limit exposure to overhead hazard as the new snow settles in - new wind slab and dry loose activity will likely step down into the basal weakness resulting in large avalanches.

Confidence

Moderate

Avalanche Summary

Patrol 93N noted a few natural avalanches - one deep persistent slab avalanche size 2.5 PR slopes, one loose dry starting in the alpine stepping to the basal weakness size 2.5 across from Mnt Coleman, and isolated dry loose avalanches up to size 1.5 on steep features in the Parker Ridge area.

Don't forget to post avalanche observations to the MIN.

Snowpack Summary

15-20cm new snow fell on Monday in the Icefields area; up to 10cm in the Maligne area. This new snow covers a sun crust on low elevation steep southerly slopes, old wind slab in expose areas, and surface facets in sheltered terrain. Moderate southwest winds are forming new wind slab immediate lees. The mid-pack is 20 to 40cm of low density facetted snow. The lower snowpack is generally weak with large facets and depth hoar at the base. Snowpack depth varies from 60 to 170cm.

Weather Summary

Residual cloud and with isolated flurries possible on Wednesday. Winds will be westerly and light with the freezing level at valley bottom. A building surface ridge of high pressure will bring a clearing trend Thursday into the weekend - daytime freezing level rising to 1500m on Friday.

Detailed weather forecasts from Avalanche Canada: https://avalanche.ca/weather/forecast

Terrain and Travel Advice

If triggered, wind slabs avalanches may step down to deeper layers resulting in larger avalanches.
Avoid shallow, rocky areas where the snowpack transitions from thick to thin.

Problems

Wind Slabs

Wind Slab avalanches are the release of a cohesive layer of snow (a slab) formed by the wind. Wind typically transports snow from the upwind sides of terrain features and deposits snow on the downwind side. Wind slabs are often smooth and rounded and sometimes sound hollow, and can range from soft to hard. Wind slabs that form over a persistent weak layer (surface hoar, depth hoar, or near-surface facets) may be termed Persistent Slabs or may develop into Persistent Slabs.

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.