Avalanche Forecast

Archived

Feb 6th, 2023–Feb 7th, 2023

Alpine

Natural avalanches unlikely, human triggered possible.

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.

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 for the best riding and the lowest avalanche danger. In the last few days, riders have triggered wind slab avalanches below ridgecrests, and in crossloaded gullies.

Confidence

High

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.

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

Monday Night

Cloudy. Possible trace of snow expected. Moderate to strong northwest ridgetop wind. Treeline temperatures -3 °C, freezing level 1700 m.

Tuesday

Cloudy. 1-2 cm of snow expected. Strong southwest ridgetop wind. Treeline temperatures -5 °C, freezing level 1700 m.

Wednesday

Mostly cloudy. 10-15 cm of snow expected overnight, possibly more in the south end of the region through the day, depending on the track of the storm. Moderate northwest or west ridgetop wind. Treeline temperatures around -9 °C.

Thursday

Mostly sunny. No new snow expected. Strong west or southwest ridgetop wind. Treeline temperatures increasing through the day to -2 °C.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

Approach lee and cross-loaded slopes with caution.
Small avalanches can have serious consequences in extreme terrain. Carefully evaluate your line for wind slab hazard before you commit to it.

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.