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Avalanche Forecast

Jan 8th, 2018–Jan 9th, 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
3: Considerable
The avalanche danger rating below treeline will be considerable
Alpine
2: Moderate
The avalanche danger rating in the alpine will be moderate
Treeline
3: Considerable
The avalanche danger rating at treeline will be considerable
Below Treeline
3: Considerable
The avalanche danger rating below treeline will be considerable
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
3: Considerable
The avalanche danger rating below treeline will be considerable

Regions: South Rockies.

Lots of uncertainty in the snowfall forecast for Tuesday and Wednesday. If it's dumping snow, consider the avalanche danger high.

Confidence

Low - Forecast snowfall amounts are uncertain

Weather Forecast

TUESDAY: Cloudy with snow. Snowfall amounts are hard to call. One senior meteorologist is predicting a 'Fernie effect', which could bring up to 40 cm of dry snow to parts of the South Rockies in short order late in the day. Light to moderate winds. Alpine temperature near -6.WEDNESDAY: Moderate westerly winds. Light snow. Alpine temperature near -15.THURSDAY: Moderate to strong winds. Light snow. Alpine temperature near -15.

Avalanche Summary

A timber sledder triggered and was caught in a small avalanche on a road cut on Sunday. It occurred a little below treeline, south of the Crowsnest. Avalanche conditions seem especially touchy in this type of terrain right now. Give extra thought to the presence of terrain traps like roads, gullies and trees. Even a small avalanche can have increased consequences in combination with a terrain trap.Reports over the last few days have been limited, but recent whumpfing and a bunch of  persistent slabs last week are all evidence of this problem. With warming or increased load by snow and/or wind-loading, persistent slab activity is likely to increase again.

Snowpack Summary

The snowpack is variable across the region, but the two key concerns are touchy persistent slabs and wind slabs. Wind slabs may exist lower on the slope than normal, due to recent extreme south-west winds. In some parts of the region, windward alpine slopes are scoured; and variable wind slabs are found at treeline and alpine elevations. A touchy weak layer from mid-December (predominantly feathery surface hoar crystals and/or a sun crust) is found at treeline and below. Slabs are failing very easily on this layer with the weight of a person or machine.Deeper in the snowpack, an early season rain crust and sugary facets make up the picture. Overall snowpack depths are variable across the region. It's generally shallower in the east.

Avalanche Problems

Persistent Slabs

New snow may overload an already touchy weak layer, making avalanches especially likely in below treeline terrain.
Avoid avalanche terrain around treeline.Avoid exposure to terrain traps where the consequences of a small avalanche could be serious.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Likely

Expected Size: 1 - 3

Wind Slabs

Wind slabs can be found at treeline and alpine elevations. Recent extreme winds have stripped some aspects and may have left wind slabs further down slope than normal.
Back off if you encounter whumpfing, hollow sounds or shooting cracks.Use ridges or ribs to avoid areas of wind loaded snow.

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

Elevations: Alpine, Treeline.

Likelihood: Possible - Likely

Expected Size: 1 - 2