Avalanche Forecast

Issued: Feb 20th, 2018 3:49PM

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

Avalanche Canada swerner, Avalanche Canada

The snow is heavily wind-affected at all elevations. Stick to sheltered trees to find the best and safest riding.

Summary

Confidence

High - The weather pattern is stable

Weather Forecast

A fairly benign weather pattern expected for Wednesday and Thursday with some new snow on Friday.Wednesday/ Thursday: Cloudy with sunny periods. Alpine temperatures will see a high of -14 with light northeast winds. Friday: Overcast with flurries and an alpine high of -11. New snow amounts 5-10 cm with ridgetop winds generally light from the west but gusting up to 50 km/hr.

Avalanche Summary

Wind had been the name of the game. On Monday, several skier triggered wind slabs up to size 1 were reported. One failed down 20 cm, running on a buried crust on a steep convex terrain feature. This was on a SE aspect at 1800 m. The other was on a NW-N aspect at 2000 m and triggered from a wind loaded pocket. With little change in the weather forecast natural avalanche activity will subside, but human triggers remain possible.The region has not seen a persistent slab avalanche report in over a week, and with the fairly benign weather pattern I don't expect them to fail by natural cause. Although the likelihood of triggering a persistent slab is gradually decreasing, the consequences remain high.

Snowpack Summary

Strong and gusty wind from various directions (primarily northeast) has scoured some exposed slopes and formed fresh wind slabs on others. Sheltered terrain, especially in the trees has 30-50 cm of low density snow from last weekend's storm. A crust layer can be found beneath the storm snow on sun-exposed slopes and below 1800 m.Weak layers that formed in January and December are gradually gaining strength. The layers include several surface hoar and facet layers buried 1-2 m below the surface. No avalanches have been reported on these layers for the past week and snowpack tests are showing improved bonding. Despite these signs, avalanche professionals are still treating these layers with respect and being cautious around shallow start zones and big avalanche paths.

Problems

Wind Slabs

An icon showing Wind Slabs
Strong wind from various directions has redistributed 30-50 cm of recent snow into reactive slabs at all elevations.
Watch for whumpfing, hollow sounds, shooting cracks or recent avalanches.Use ridges or ribs to avoid pockets of wind loaded snow.If triggered the wind slabs may step down to deeper layers resulting in large avalanches. Use extra caution or avoid shallow start-zones and big avalanche paths.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

1 - 2.5

Valid until: Feb 21st, 2018 2:00PM