Archived

Avalanche Forecast

Dec 15th, 2019–Dec 16th, 2019

Alpine

2: Moderate

The avalanche danger rating in the alpine will be moderate

Treeline

2: Moderate

The avalanche danger rating at treeline will be moderate

Below Treeline

1: Low

The avalanche danger rating below treeline will be low

Alpine

2: Moderate

The avalanche danger rating in the alpine will be moderate

Treeline

2: Moderate

The avalanche danger rating at treeline will be moderate

Below Treeline

1: Low

The avalanche danger rating below treeline will be low

Alpine

2: Moderate

The avalanche danger rating in the alpine will be moderate

Treeline

2: Moderate

The avalanche danger rating at treeline will be moderate

Below Treeline

1: Low

The avalanche danger rating below treeline will be low

Regions: Lizard-Flathead.

A stable weather pattern is forecast for the next few days with flurries at the end of the week.

Confidence

Moderate - Confidence is due to a stable weather pattern with little change expected.

Weather Forecast

Sunday Night: Cloudy with starry breaks. Alpine temperature -13 C. West wind 25-35 km/hr.

Monday: Mix of sun, cloud, and isolated flurries. Alpine temperature -10 C. Southwest wind 25-45 km/hr.

Tuesday: Partly cloudy, partly sunny. Alpine temperature -9 C. Southwest wind 25-45 km/hr.

Wednesday: Mix of sun and cloud. Alpine temperature -9 C. West wind 15-40 km/hr.

Avalanche Summary

On Saturday, 2 large (size 2) natural storm slab avalanches were reported initiating from steep north-north east aspects in the alpine. Around Fernie, the new snow was reactive to skier tracks.

Avalanche activity late last week was primarily limited to small wind slab avalanches (size 1) triggered with explosives. On Thursday there was a report of a size 2.5 storm slab avalanche on a northeast aspect in the alpine, which scoured down to a crust near the base of the snowpack.

Snowpack Summary

Recent new snow and wind has likely formed fresh wind slabs at upper elevations. In sheltered areas 30-40 cm of snow from last weekend is gradually settling. Crust layers from November and October can be found 40-100 cm below the surface. These layers produced large avalanches with explosive triggers last weekend, but since then have appeared to gain strength. Large avalanches on these layers may still be possible to trigger in steep rocky terrain. Snowpack depths range between 50-100 cm at higher elevations and taper rapidly below treeline.

Check out this MIN reporting conditions on Saturday at Harvey Pass.

Avalanche Problems

Wind Slabs

Triggering wind slab avalanches is most likely at higher elevations where the wind has redistributed recent new snow into the lee of terrain features.

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

Elevations: Alpine.

Likelihood: Possible

Expected Size: 1 - 2

Persistent Slabs

The likelihood of triggering a large avalanche on one of the crusts and weak layers in the lower snowpack is gradually reducing, but the consequence of doing so is high.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Unlikely

Expected Size: 2 - 3