Avalanche Forecast

Archived

Feb 12th, 2023–Feb 13th, 2023

Alpine

Natural and human triggered avalanches likely.

Treeline

Natural avalanches possible, human triggered probable.

Below Treeline

Natural avalanches unlikely, human triggered possible.

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches possible, human triggered probable.

Below Treeline

Natural avalanches unlikely, human triggered possible.

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely.

Regions

Cirrus-Wilson, Icefields.

There is a 20cm winter storm warning for Jasper to Saskatchewan crossing. Higher amounts may occur locally particularly with strong winds. This new input is expected to raise the avalanche hazard over the next couple days.

Confidence

Moderate

Avalanche Summary

Sunday's Icefield patrol had windy conditions and poor visibility. Nothing new was observed. Natural avalanches up to size 2.5 were observed in the icefields region, initiating in alpine and exposed tree line features on Saturday.

Avalanche control with explosives on Wednesday resulted in numerous large avalanches running to the bottom of the avalanche paths.

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

Snowpack Summary

Sunday night's storm may add 20-30cm of new snow and windy conditions. This will be redistributed by the winds and add to the 10 to 30cm that fell last week creating wind slabs in the alpine and exposed tree line. Generally, the mid and bottom of the snowpack is weak facets with depth hoar at the base.

Weather Summary

A 20cm storm warning is issued for Highway 93 Jasper to Saskatchewan River Crossing beginning Sunday evening. Locally amounts may increase to 30cm. Expect strong southwesterly winds gusting to 60 km/h. The storm will taper off Monday afternoon.

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

Terrain and Travel Advice

Continue to make conservative terrain choices while the storm snow settles and stabilizes.
Be careful to keep storm day fever from luring you out into bigger terrain features.

Problems

Storm Slabs

Storm Slab avalanches are the release of a cohesive layer (a slab) of new snow that breaks within new snow or on the old snow surface. Storm-slabs typically last between a few hours and few days (following snowfall). Storm-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.

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.