Avalanche Forecast

Issued: Dec 13th, 2018 3:50PM

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

Avalanche Canada jfloyer, Avalanche Canada

A Special Public Avalanche Warning is in effect for this region. Strong winds and warming will maintain high danger even though snow amounts may start to taper off.

Summary

Confidence

Moderate - Freezing levels are uncertain on Friday

Weather Forecast

THURSDAY NIGHT: Around 15 cm new snow above 1600 m.FRIDAY: A mix of sun and cloud in the morning with heavy rain/snow developing in the afternoon (amounts of about 20 cm/mm). Very strong southerly winds (up to 100 km/h at ridgetop). Freezing level around 1700 m.SATURDAY: A mix of sun and cloud. Winds becoming light southwesterly. Freezing level around 900 m.SUNDAY: 20 cm or so new snow with a freezing level of around 1200 m. Strong southerly winds.

Avalanche Summary

A widespread natural avalanche cycle was reported on Wednesday and Thursday. Natural avalanches are likely to continue on Friday. Human-triggered avalanches will remain a concern over the weekend.

Snowpack Summary

Snowfall beginning Sunday has deposited up to 130 cm in the Sea to Sky region. Strong to extreme southwesterly winds have accompanied the new snow and the weather forecast is calling for additional snowfall amounts to accumulate. Buried under the new snow is a weak surface layer sitting over 20-30 cm of low density faceted snow. The new snow is not bonding well with the old surface layer, has slab-like properties, and is reacting to skier traffic.Prior to this storm, alpine snowpack depths varied around 150-200 cm, with an early November crust at bottom of the snowpack (down 100-120 cm). This crust appears to be breaking down at higher elevations and has been unreactive to snowpack tests. Snowpack depths disappear quickly with decreasing elevations (starting around 1800 m).

Problems

Storm Slabs

An icon showing Storm Slabs
Very strong winds, lots of recent new snow and a warming trend will make storm slab avalanches very likely.
Stick to simple terrain and be aware of what is above you at all times.Avoid exposure to overhead avalanche terrain, large avalanches may reach the end of run out zones.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Very Likely - Certain

Expected Size

1.5 - 3

Valid until: Dec 14th, 2018 2:00PM