Avalog Logo

Avalanche Canada swerner, Avalanche Canada

Lizard Range and Flathead Avalanche Forecast

Dec 5th, 2016 3:51PM

The alpine rating is considerable, the treeline rating is moderate, and the below treeline rating is below threshold. Known problems include Storm Slabs.

Fresh storm slabs that formed over the weekend may be reactive to rider triggers especially on slopes that have seen more wind loading.

Summary

Confidence

Moderate - Due to the number of field observations

Weather Forecast

The arctic front dominates the province bringing some of the coldest temperatures of the season. Some light snow accumulations can be expected overnight and into tomorrow. Alpine temperatures will dip to -20 accompanied by light winds from the east. The weather pattern will likely start to change Thursday afternoon as the next pacific frontal system tracks onto the south coast. The battle between the cold arctic air and the warm pacific air will bring cloudy unsettled conditions and new snowfall amounts.

Avalanche Summary

On Monday, numerous loose dry avalanches up to size 1 were reported after the storm as well as a natural size 2.5 storm slab from a northeast aspect above 1800 m. The crown was 20-100 cm thick, 150-200 m wide and running 500 m in length. On Saturday, numerous natural storm slab avalanches were reported. These avalanches were up to size 2 and running on north-northeast aspects above 1700 m. Explosive control also triggered several slabs up to size 2. The crowns were 20-40 cm deep and running up to 160 m in length. These slabs were mostly failing on an old storm interface and reports haven't indicated any avalanche actively on the buried November crusts.

Snowpack Summary

New storm slabs and wind slabs have formed on open leeward slopes and behind terrain features. The threshold for avalanches has been exceeded at treeline and in the alpine as reports suggest that the snow depth at treeline is typically 110-150 cm but a report from the east side of region shows only 80 cm at treeline. The snowpack is still developing below treeline and has yet to reach threshold. Limited reports suggest the crust from the middle of November is down 50-80 cm and the crust from early November is down 80-110 cm.

Problems

Storm Slabs

An icon showing Storm Slabs
New snow accompanied by strong winds have formed fresh and reactive storm slabs at upper elevations.
Be alert to conditions that change with elevation. Use a conservative approach to terrain.Avoid freshly wind loaded features.

Aspects:

All aspects.

Elevations:

Alpine, Treeline.

Likelihood

Likely - Possible

Expected Size

1 - 2

Valid until: Dec 6th, 2016 2:00PM