Avalanche Forecast

Issued: Feb 4th, 2018 4:46PM

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

Avalanche Canada mgrist, Avalanche Canada

Wind slabs and cornices are the main concerns right now: Give both a wide berth and limit your exposure to overhead hazard.

Summary

Confidence

Moderate - Due to the number of field observations

Weather Forecast

Monday: Mainly cloudy with isolated flurries (up to 5 cm possible) / Light to moderate north westerly winds / Freezing level at 1200mTuesday: Isolated flurries (5cm possible) / Light to moderate south westerly winds / Freezing level 1000m. Wednesday: 5-10cm of snow / Moderate gusting strong west winds / Freezing level at 1600m

Avalanche Summary

On Sunday, ski cutting produced several size 1 to 1.5 soft slabs on immediate down wind (lee) features. Expect wind slabs to remain reactive to human triggers as winds continue to be moderate to strong with small amounts of new snow available for transport.  On Saturday we received reports of a skier triggered size 1.5 avalanche near Whistler on a north west aspect around 2100m.

Snowpack Summary

Over the past two days 7-12 cm of new snow has fallen. Temperatures were steady near +1 at tree line on Sunday afternoon. Winds, however, have been consistently strong from the south, creating fresh wind slabs in exposed downwind (lee) terrain. At lower treeline and below, generally light amounts of snow or rain now overlie a melt-freeze crust which formed during Monday's warm storm from a week ago.The new snow adds to the 170cm of snow that fell during the last few weeks of January. These series of storms were accompanied by strong to extreme winds which resulted in extensive scouring and impressive cornice growth in upper elevation terrain. These accumulations sit on a crust from mid-January which generally shows signs of bonding to the overlying snow; however, it has the potential to "wake-up" with a large trigger such as a cornice fall.Below this, the snowpack is thought to be generally strong and well-settled.

Problems

Wind Slabs

An icon showing Wind Slabs
Recent winds have created pockets of reactive soft slab below ridge crests and on immediate down wind (lee) features at higher elevations.
Be cautious as you transition into wind affected terrain.Be alert to conditions that change with elevation.Stay off recent wind loaded areas until the slope has had a chance to stabilize.

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2

Cornices

An icon showing Cornices
Heavy snowfall and high winds a week ago formed fragile cornices. These monsters may surprise with nasty consequences. Use extra caution around ridge crests.
Give cornices a wide berth when travelling on or below ridges.Falling cornices may trigger large avalanches on the slopes below.

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1.5 - 2.5

Valid until: Feb 5th, 2018 2:00PM