Avalanche Forecast

Archived

Feb 28th, 2023–Mar 1st, 2023

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.

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely.

Regions

Kananaskis, Bow Valley, Highwood Pass, North 40, Spray - KLakes.

The recent snow is providing good skiing in low avalanche hazard areas. Human triggering of wind slabs is still a concern. Conservative route selection is advised.

Confidence

Moderate

Avalanche Summary

No new avalanches were observed or reported today.

Snowpack Summary

We have had 10-15cm of recent snow that has not yet been touched by the wind. This sits on top of two generations of wind slabs: the Feb26 wind slab from this past week's wind event and the Feb. 19 wind slab which is about 30cm down. A test profile near Burstall Pass showed easy resistant planar results on the Feb 19 wind slab. The alpine is still quite variable in terms of snow depth; in deeper areas the mid-pack is strong. The November facets make up the bottom 50-70cm of the snowpack and there is anywhere from 40-110cm sitting on top of it depending on elevation. Our biggest concern is triggering the wind slab which then has a high potential to step down to the November basal layer. Good skiing can still be found in low avalanche hazard areas at all elevations. The wind slabs have slowly started to bond with the other interfaces but there is still a concern for human triggering.

Weather Summary

Wednesday will bring cloudy skies with light flurries(2cm if you round up). Temperatures in the alpine will climb to a high of -10c. Winds will start off Light from the West and increase to Strong from the West throughout the day

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
Be aware of the potential for surprisingly large avalanches due to deeply buried weak layers.
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.