Avalanche Forecast

Issued: Dec 28th, 2016 3:47PM

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

Avalanche Canada rbuhler, Avalanche Canada

Heavy snowfall on Thursday with strong winds and mild temperatures is expected to form widespread storm slabs and drive the danger to HIGH. Travel in avalanche terrain is not recommended.

Summary

Confidence

High -

Weather Forecast

The last major low pressure system is expected to bring heavy snowfall to the region Wednesday overnight and Thursday. 15-25 cm is expected Wednesday overnight and 30-50 cm is expected on Thursday. Alpine wind is forecast to be strong to extreme from the southwest on Thursday and freezing levels are expected to reach around 800 m elevation. Mostly dry and sunny conditions are expected for Friday with light alpine wind and freezing levels around 600 m. A weak storm pulse is forecast to bring around 5 cm of snow on Saturday with strong alpine wind from the northwest.

Avalanche Summary

A widespread natural avalanche cycle was observed on Monday evening and overnight. These were storm slab avalanches up to size 2 with a typical slab thickness of 20-40 cm. No new avalanches were observed on Tuesday. On Thursday, another natural avalanche cycle is expected similar to the one that occurred on Monday night. Heavy snowfall and mild temperatures are expected to quickly form new slabs. In wind exposed terrain, expect thick touchy slabs in leeward terrain features.

Snowpack Summary

30-50 cm of new snow has accumulated since Monday. This new snow sits over a variable interface which consisted of wind affected surfaces, faceted (sugary) snow, or surface hoar. Recent reports suggest this storm snow is now well bonded except places where surface hoar may be preserved. Recently strong southerly winds have formed new wind slabs in leeward and cross loaded features in wind exposed terrain. A crust that formed a week ago is likely down around 50-70 cm. Below this crust, the snowpack is generally considered well settled and stable.

Problems

Storm Slabs

An icon showing Storm Slabs
Heavy snowfall, strong winds, and mild temperatures are expected to form widespread touchy storm slabs on Thursday.
Avoid all avalanche terrain during periods of heavy loading from new snow, wind, or rain.Use very conservative route selection, choose low angled and supported terrain with low consequence.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Very Likely

Expected Size

1 - 3

Valid until: Dec 29th, 2016 2:00PM