Avalanche Forecast

Archived

Feb 4th, 2023–Feb 5th, 2023

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely, human triggered possible.

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely, human triggered possible.

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely, human triggered possible.

Regions

Akamina, Crowsnest North, Crowsnest South.

Choose terrain that is sheltered from the wind. In the last few days, riders have triggered wind slab avalanches below ridgecrests, and in crossloaded gullies.

Check out this MIN report from Crowsnest Pass. It's a great example of where the wind slab problem can be found.

Confidence

Moderate

Avalanche Summary

On Friday, a large (size 2), rider triggered, windslab avalanche was reported south of Crowsnest Pass. It occured in an open, cross-loaded feature below tree line on a north facing slope.

On Saturday, in neighboring Waterton National park, a similar but smaller (size 1.5) rider triggered avalanche occured on a southeast facing slope below treeline.

Small (size 1) isolated pockets of wind slabs continue to be triggered by riders in lee terrain features. Wind slabs may linger directly lee of ridges at high elevations. See this MIN post for an example.

Please continue to share any observations or photos on the Mountain Information Network.

Snowpack Summary

5 to 10 cm of recent snow coupled with moderate to strong southwest winds has built wind slabs in lee and crossloaded features at alpine and treeline elevations, and in open features below treeline. A melt-freeze crust can be found at 2100 m and below at variable depths, on the surface on windward slopes, and buried 15 to 20 cm in lees. Wind slabs may be more reactive where they sit on this crust.

The middle of the snowpack is consolidated. Weak faceted grains exist near the base of the snowpack.

The average snowpack depth is 120 cm. Up to 200 cm can be found in wind-loaded areas.

Weather Summary

Saturday Night

Mostly cloudy, no new snow expected. Moderate southwest ridgetop wind, trending to strong at higher elevations. Treeline temperature -3 °C, freezing level falling to 1000 m.

Sunday

Mostly cloudy. Possible trace of snow expected. Moderate southwest ridgetop wind, trending to strong at higher elevations. Treeline temperature -3 °C, freezing level rising to 1700 m.

Monday

Mostly sunny. Possible trace of snow overnight and through the day. Moderate southwest ridgetop wind, trending to strong at higher elevations. Treeline temperatures -2 °C, freezing level 1700 m.

Tuesday

Mostly cloudy. 0-5 cm of snow expected. Strong southwest ridgetop wind, trending to extreme at higher elevations. Treeline temperatures -2 °C, freezing level 1700 m.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

Approach lee and cross-loaded slopes with caution.
Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
Small avalanches can have serious consequences in extreme terrain. Carefully evaluate your line for wind slab hazard before you commit to it.
Keep your guard up at lower elevations. Wind slab formation has been extensive.

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.