Avalanche Forecast

Archived

Feb 24th, 2024–Feb 25th, 2024

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches possible, human triggered probable.

Below Treeline

Natural avalanches possible, human triggered probable.

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, human triggered possible.

Regions

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

The incoming storm could bring 30cm and moderate to strong winds by Sunday evening-Monday morning but weather models are not in agreement. It would be wise to pull the reins in until one can determine the impacts of the new snow load. There will be an increase in natural activity.

Confidence

Low

Avalanche Summary

The field team observed several size 2 wind slabs in the Miette lake area mainly on East aspects in the alpine. Several other 12-24hr old similar avalanches were noted in the same area. Feb 23 three avalanches occurred in the Churchill group originating in steep, rocky, unsupported terrain ranging in size from 1.5 to 2.5. Expect increased avalanche activity next couple of days as the storm brings new snow and winds.

Snowpack Summary

15-20cm of snow arrived in the past 24 hours at the Parkers ridge area. Much less at Coleman and Maligne. There is a storm brewing with another 20cm to arrive now until Monday. A 1-3cm thick crust is down 20-40 cm on polar aspects up to 2500m and extends as high as 2800m on solar aspects. The mid-pack is faceted with basal depth hoar and well developed facets near ground. HS ranges from 60 to 100cm. The Parkers manual weather station at 2000m might crest 1 meter with this storm input.

Weather Summary

The Mountain Weather Forecast is available at Avalanche Canada https://avalanche.ca/weather/forecast

Saturday night could have 25-65km/h winds and 5cm of snow. Sunday will bring upwards of 14cm of snow, -6 °C, and light gusting strong SW winds. The storm will leave by Monday morning and the temperature will plummet to -26 °C.

Terrain and Travel Advice

Continue to make conservative terrain choices while the storm snow settles and stabilizes.
Fresh snow rests on a problematic persistent slab, don't let good riding lure you into complacency.

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.

Persistent Slabs

Persistent Slab avalanches are the release of a cohesive layer of snow (a slab) in the middle to upper snowpack, when the bond to an underlying persistent weak layer breaks. Persistent layers include: surface hoar, depth hoar, near-surface facets, or faceted snow. Persistent weak layers can continue to produce avalanches for days, weeks or even months, making them especially dangerous and tricky. As additional snow and wind events build a thicker slab on top of the persistent weak layer, this avalanche problem may develop into a Deep Persistent Slab.

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.