Archived

Avalanche Forecast

Jan 30th, 2013–Jan 31st, 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

2: Moderate

The avalanche danger rating below treeline will be moderate

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

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

2: Moderate

The avalanche danger rating at treeline will be moderate

Below Treeline

2: Moderate

The avalanche danger rating below treeline will be moderate

Regions: Kootenay Boundary.

Confidence

Fair - Timing or intensity of solar radiation is uncertain on Friday

Weather Forecast

Thursday: Moderate NW winds. Alpine temperature near -4. Light snow.Friday: Light W winds. Alpine temperature near -2. No snow.Saturday: Light W winds. Alpine temperature near 0. Sunny skies, with valley cloud.

Avalanche Summary

Size 1 to 2 loose dry avalanches have been failing with natural and human triggers in steep terrain. A few slabs to size 2 have also been observed, in some cases failing on a crust/facet interface below recent storm snow.

Snowpack Summary

NW winds have redistributed 15-40 cm of recent snow into soft or hard slabs on lee slopes in the alpine and at treeline. In areas not affected by the wind, loose snow is sluffing easily in steep terrain. The new snow sits on a variety of old surfaces including surface hoar, facets, hard slabs and crusts. Deeper, about 50-60cm down, a weak interface buried in early January exhibits moderate to hard, sudden results in snowpack tests. The snowpack below this is generally well bonded.

Avalanche Problems

Wind Slabs

Be alert for wind slabs behind terrain breaks such as ridges and ribs.

Stay off recent wind loaded areas until the slope has had a chance to stabilize.>Use ridges or ribs to avoid pockets of wind loaded snow.>

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

Elevations: Alpine, Treeline.

Likelihood: Possible - Likely

Expected Size: 1 - 4

Persistent Slabs

A mixed bag of weak interfaces is buried about 40 cm down. With forecast warming temperatures, it’s possible that the snow above will form into a more cohesive slab over the next few days.

Dig down to find and test weak layers before committing to a line.>Whumpfing, shooting cracks and recent avalanches are all strong indicators of an unstable snowpack.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood: Unlikely - Possible

Expected Size: 1 - 4