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Archived

Avalanche Forecast

Jan 13th, 2018–Jan 14th, 2018
Alpine
3: Considerable
The avalanche danger rating in the alpine will be considerable
Treeline
3: Considerable
The avalanche danger rating at treeline will be considerable
Below Treeline
2: Moderate
The avalanche danger rating below treeline will be moderate
Alpine
3: Considerable
The avalanche danger rating in the alpine will be considerable
Treeline
3: Considerable
The avalanche danger rating at treeline will be considerable
Below Treeline
2: Moderate
The avalanche danger rating below treeline will be moderate
Alpine
3: Considerable
The avalanche danger rating in the alpine will be considerable
Treeline
3: Considerable
The avalanche danger rating at treeline will be considerable
Below Treeline
2: Moderate
The avalanche danger rating below treeline will be moderate

Regions: Little Yoho.

This is a good time to be conservative in your terrain choices and minimize exposure to avalanche terrain. The chances of human triggered avalanches are quite high and as temperatures increase we will start to see more natural activity as well.

Weather Forecast

The winds will decrease on Sunday afternoon and the gradual warming continues as the high pressure system arrives. On Monday and Tuesday we expect an inversion to build with alpine temperatures forecast to be just above freezing. Valley bottom temperatures will remain at or below freezing. No significant precipitation is expected.

Snowpack Summary

Moderate to strong W winds and warming temperatures are forming wind slabs in the alpine. There is 40-65 cm over the Dec.15 persistent weak layer of surface hoar at treeline. This is becoming reactive to skiers and producing easy to moderate results as shown in this video from Mt Field. Below this is a faceted but generally supportive snow pack.

Avalanche Summary

A couple natural avalanches up to size two from the past 48 hrs were observed at treeline in the Little Yoho region. These had failed on the Dec 15 surface hoar interface. Sluffing was observed in the alpine due to strong West winds. Lots of whumphing and cracking in open glades at treeline during a trip to Mt Field on Saturday.

Confidence

Freezing levels are uncertain on Monday

Avalanche Problems

Persistent Slabs

There is a widespread weak layer of surface hoar from Dec 15th down 40-60 cm with a stiff enough slab over it to start producing avalanches. Be very careful and travel conservatively even if you observe no avalanches.
Avoid open slopes and convex rolls at treeline where buried surface hoar may be preserved.Watch for whumpfing, hollow sounds, shooting cracks or recent avalanches.

Aspects: All aspects.

Elevations: All elevations.

Likelihood: Possible - Likely

Expected Size: 1 - 3

Wind Slabs

New wind slabs were forming at treeline and in the alpine Saturday with the moderate to strong West winds and warmer temperatures. Watch for the changing feel of the snow under your feet and be wary of areas with denser surface snow over weaker snow.
Use caution in lee areas. Recent wind loading has created wind slabs.If triggered the wind slabs may step down to deeper layers resulting in large avalanches.

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

Elevations: Alpine, Treeline.

Likelihood: Possible - Likely

Expected Size: 1 - 2