Avalanche Forecast

Issued: Feb 1st, 2019 5:31PM

The alpine rating is considerable, the treeline rating is considerable, and the below treeline rating is considerable. Known problems include Persistent Slabs and Wind Slabs.

mbender, Avalanche Canada

Lizard-Flathead.

Snowfall amounts for Friday night are uncertain. If the new snow amount is locally 30 cm or more the avalanche danger will be HIGH. Click here for summary of the current conditions and what to expect with some new snow.

Summary

Confidence

Low - Forecast snowfall amounts are uncertain on Saturday

Weather Forecast

FRIDAY Night: Snow, accumulation 15-25 cm, moderate to strong southwest winds, alpine temperature -3 C, freezing level 1100 m.SATURDAY: Cloudy with flurries, accumulation up to 5 cm, light to moderate southwest winds, alpine temperature -2 C, freezing level 1300 m.SUNDAY: Cloudy with isolated flurries, light east winds, alpine temperature -20 C.MONDAY: Mix of sun and cloud, light east wind, alpine temperature -25.

Avalanche Summary

A small wind slab avalanche was triggered by a skier on Thursday on an easterly aspect. The likelihood of triggering avalanches is expected to increase with incoming snow with strong southwest winds. Click here to see a recent Instragram post regarding the sensitivity of a recently buried weak layer of surface hoar in the Flathead.

Snowpack Summary

New snow Friday night is expected to fall with strong southwest winds. Expect to find new wind slabs form in lee and cross-loaded terrain features near ridges. The new snow will overly feathery surface hoar crystals, previously wind-affected snow, and a melt-freeze crust on southerly aspects.Buried around 20 to 50 cm, a weak layer of surface hoar may be found on shady and sheltered slopes. Use added caution between 1500 m and 1900 m, where this layer is most prominent. On southerly aspects, the snow overlies a hard melt-freeze crust all the way to the mountain tops.The remainder of the snowpack is generally well-settled. Thin snowpack areas, such as in the east of the region, may find weak and sugary faceted grains near the base of the snowpack.

Problems

Persistent Slabs

Around 20 to 60 cm of snow sits above a weak layer of surface hoar and a melt-freeze crust. The surface hoar is likely best preserved in shaded and sheltered areas between 1500 m and 1900 m. The crust exists on southerly aspects at all elevations.

Make observations and assess conditions continually as you travel.Watch for signs of instability such as whumpfing, cracking, or recent avalanches.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 2

Wind Slabs

New snow Friday night combined with strong southwest winds is expected to create windslabs in lee and cross-loaded terrain depressions, particularly near ridges.

Use caution in freshly wind-loaded features, especially near ridge crests and in steep terrain.If triggered the wind slabs may step down to deeper layers resulting in large avalanches.

Aspects: North, North East, East, South East, North West.

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 2

Valid until: Feb 2nd, 2019 2:00PM