Archived

Avalanche Forecast

Feb 22nd, 2018–Feb 23rd, 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.

Heads up! Artillery fire is planned for the day. Due to recent construction, new artillery targets need to be sighted in. As always, check to make sure the area you want to ski / ride are open.

Weather Forecast

A stellar day to be in the alpine, mainly sunny skies with periods of clouds rolling through with a chance of isolated convective flurries throughout the day. Temps ranging from -11 to -19 with light ridgetop winds. Temps gradually warming and the first amount of significant snow will arrive over the weekend.

Snowpack Summary

Cold temps promoting facetting of the upper snowpack. Previous strong northerly 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 in the past two days. 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 several 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 over the past week.

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

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Possible

Expected Size: 1.5 - 2.5

Cornices

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

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

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. Large triggers such as cornice fall may also wake up these deeper weak layers resulting in large avalanches.

Avoid thin, rocky or unsupported slopes.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Unlikely - Possible

Expected Size: 2.5 - 3.5