Archived

Avalanche Forecast

Jan 31st, 2013–Feb 1st, 2013

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: Banff Yoho Kootenay.

Warming and solar effect on Saturday may cause local instabilities and increased danger on southerly aspects.

Weather Forecast

Weak precipitation and warm teme\peratures with a westerly flow. Clearing for Saturday may create solar issues with the warm temperatures.

Snowpack Summary

Two main layers in the upper pack are Jan 23 and Jan 4 surface hoar/ facets or suncrust down 25 & 55. Major problem is wind slabs in all open areas easily triggerable in steep terrain.

Avalanche Summary

Very little activity. Some wind slabs in steep terrain to size 2. One older size 2 slab (48 hrs + ) in Kootenay may have failed on surface hoar down 50.

Confidence

Avalanche Problems

Wind Slabs

Isolated wind slabs in steep terrain features may be human triggered or run naturally with slight additional loading.

Be cautious as you transition into wind affected terrain.The recent snow may now be hiding windslabs that were easily visible before the snow fell.

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

Elevations: Alpine, Treeline.

Likelihood: Possible

Expected Size: 1 - 2

Persistent Slabs

In Kootenay and Yoho there is a buried surface hoar and/or crust layer down about 50 cm. This layer may be triggerable on steep terrain features.

Avoid open slopes and convex rolls at and below treeline where buried surface hoar may be preserved.

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

Elevations: Alpine.

Likelihood: Possible

Expected Size: 1 - 3

Persistent Slabs

Hard slabs from previous high winds have been buried by recent storm snow. These slabs have been unreactive to skier triggering, but new wind loading may awaken them.

Be careful with wind loaded pockets

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Unlikely - Possible

Expected Size: 1 - 2