Avalanche Forecast

Issued: Feb 8th, 2018 4:23PM

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

swerner, Avalanche Canada

Sea To Sky.

When the sun pokes out natural slab and loose dry avalanche activity will likely increase.

Summary

Confidence

Moderate - Wind effect is extremely variable

Weather Forecast

Friday: A mix of sun and cloud with alpine temperatures near -9 and freezing levels dropping to valley bottom. Ridgetop winds light from the North.Saturday: Sunny. Alpine temperatures near -5 and freezing levels valley bottom. Light winds from the North.Sunday: A mix of sun and cloud. Alpine temperatures -7 and freezing levels rising to 800 m. Light winds from the northeast.

Avalanche Summary

On Thursday, avalanche control with explosives triggered numerous slab avalanches up to size 2. Cornice releases triggered wind slabs from the slopes below up to size 1.5. With colder temperatures expected this weekend, natural avalanche activity will likely taper off, but human triggering will be possible especially on leeward slopes and behind terrain features.

Snowpack Summary

Snow surfaces vary from aspect to elevation showing crusts, wind pressed and scoured conditions. In the alpine 5-15 cm of recent snow, accompanied by strong winds from the southeast have formed reactive wind slabs in leeward terrain and large looming cornices exist, they are fragile and demand respect. Treeline and below treeline elevations a melt-freeze crust has formed.An average of 170 cm of settled snow now sits on the mid-January crust 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

Wind slabs remain reactive to rider triggers, especially on leeward slopes and behind terrain features.

Be cautious as you transition into wind affected terrain.Watch for signs of instability such as whumpfing, or cracking.

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

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 2.5

Cornices

Large looming cornices exist along ridgelines. They require respect and discipline. Give them an extra wide berth from above and below.

Falling cornices may trigger large avalanches on the slopes below.Give cornices a wide berth when travelling on or below ridges.

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1.5 - 2.5

Valid until: Feb 9th, 2018 2:00PM