Archived

Avalanche Forecast

Feb 21st, 2018–Feb 22nd, 2018

Alpine

2: Moderate

The avalanche danger rating in the alpine will be moderate

Treeline

2: Moderate

The avalanche danger rating at treeline will be moderate

Below Treeline

1: Low

The avalanche danger rating below treeline will be low

Alpine

2: Moderate

The avalanche danger rating in the alpine will be moderate

Treeline

2: Moderate

The avalanche danger rating at treeline will be moderate

Below Treeline

1: Low

The avalanche danger rating below treeline will be low

Alpine

2: Moderate

The avalanche danger rating in the alpine will be moderate

Treeline

2: Moderate

The avalanche danger rating at treeline will be moderate

Below Treeline

1: Low

The avalanche danger rating below treeline will be low

Regions: Glacier.

Danger ratings have been reduced but it is still possible for large human triggered avalanches. Evaluate the terrain and the snowpack carefully.

Weather Forecast

Another abnormally cold day in Rogers Pass, mainly cloudy skies with periods of sun. No snow in the forecast, temps ranging between -23 to -16 with 10-20km/h southwest winds. Friday will be the day of change in the weather with warming temps and 10-15cm of snow by Sunday.

Snowpack Summary

Cold temps promoting facetting of the upper snowpack. Previous strong NE winds have formed reverse loaded cornices. Windslab can be expected in the alpine and exposed areas well into treeline. On solar aspects, a crust is buried 40cm. Persistent weak layers from January and December are now buried 150-200cm.

Avalanche Summary

No new avalanches observed yesterday. Skier controlled size 2.5 wind slab on Mt. Sifton and several skier controlled size 1.0 loose dry sluffs in the Hermit slide path two days ago. Several cornice failures earlier this week up to size 2.5.

Confidence

Avalanche Problems

Wind Slabs

Previous strong northerly winds have formed reverse loaded windslab at and above treeline. Windslab avalanches up to size 2.5 have been triggered by skiers or failing naturally. Avoid exposing yourself to overhead hazard.

Be careful with wind loaded pockets, especially near ridge crests and roll-overs.Watch for whumpfing, hollow sounds, and shooting cracks.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Possible

Expected Size: 1.5 - 2.5

Cornices

Cornices have been failing steadily over the past week. Cold temperatures and solar input are contributing to these failures with brittle fractures of the snow as temperatures fluctuate.

Avoid travel on slopes that are exposed to cornices overhead.Cornices become weak with daytime heating.

Aspects: All aspects.

Elevations: Alpine.

Likelihood: Possible

Expected Size: 1.5 - 2.5

Persistent Slabs

Persistent weak layers continue to linger and are most likely triggered in steep, shallow, rocky, unsupported terrain features. Larger triggers such as cornice fall may also wake these deeper weak layers resulting in larger avalanches.

Avoid thin, rocky or unsupported slopes.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Unlikely - Possible

Expected Size: 2.5 - 3.5