South Rockies

The best and safest riding will be in low-angled sheltered terrain where the snow hasn't been wind-affected.

On Thursday two notable cornice failures in the northern Elk Valley produced slabs on northeast facing ridges that stepped down to the persistent weak layer lower down. Numerous small size 1 wind slabs and loose dry avalanches were observed in the Crowsnest, as well as size 2 wind slabs by Castle Mtn.

Avalanches on the persistent weak layer are becoming less likely to trigger, but if they do, they can be large and highly destructive.

Recent snowfall of 10 to 20 cm, combined with strong southwest winds, has formed wind slabs near ridgetops and on leeward slopes facing north through east. Below 1900 m and on sun-exposed aspects, the new snow rests atop a firm crust left behind by previous warm temperatures and sun.

A persistent weak layer of surface hoar or facets from late January is buried 40 to 80 cm. This layer previously triggered large avalanches in early March, and continues to show reactivity in snowpack tests. The greatest concern is for areas lacking a thick, supportive crust under the new snow —particularly at upper elevations on northerly and easterly slopes.

Friday Night

Partly cloudy. 15 to 30 km/h southwest ridgetop wind. Treeline temperature -11 °C.

Saturday

Mostly cloudy, with 2 to 5 cm of new snow. 10 to 15 km/h southwest ridgetop wind. Treeline temperature -5 °C.

Sunday

Mostly cloudy, with 0 to 5 cm of snow. 15 to 30 km/h southwest ridgetop wind. Treeline temperature -3 °C. Freezing level rising to 1600 m.

Monday

A mix of sun and cloud. 25 to 35 km/h west ridgetop wind. Treeline temperature -5 °C. Freezing level rising to 1500 m.

More details can be found in the Mountain Weather Forecast.

• Avoid steep, rocky, and wind-affected areas where triggering slabs is more likely.
• Be mindful that deep instabilities are still present and have produced recent large avalanches.
• Choose low-angled, sheltered terrain where new snow hasn't been wind-affected.