Archived

Avalanche Forecast

Jan 15th, 2012–Jan 16th, 2012

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

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: Northwest Coastal.

Confidence

Good - -1

Weather Forecast

Arctic Air continues to sweep down from the North influencing the NW Coast. Under this pattern the region will see cold temperatures: At 1500 m on Monday you can expect a High of -20, Low of -31. Ridgetop winds will be from the E, NE at moderate values under mostly sunny skies. This pattern looks to persist through Thursday.

Avalanche Summary

Sluff & loose snow avalanches to size 1 have been reported. There are also limited reports of snow "cracking" which is indicative of wind slab formation.

Snowpack Summary

20 - 30 cm of new snow has fallen across the region since last Thursday. In wind exposed locations this new snow fell on old stubborn wind slabs. Reports from the region indicate that the new snow is bonding well to the old snow surface. Snowpack depths vary from 3.5 to 5 m across the region. In this part of the province, the mid-December surface hoar/facet combo layer is inactive as it's now 2.5 m below the snow surface. For the most part, avalanche concerns are limited to storm snow instabilities.By Monday the region should be firmly in the grasp of an outbreak of Arctic Air and while I suspect this cool dry air will help to tighten up the snowpack it will also introduce reverse wind loading which could lead to windslab development in unusual locations.

Avalanche Problems

Wind Slabs

Strong winds out of the North - East associated with Arctic Air could form fresh wind slabs in unusual locations. Watch for cross-loading in the alpine and in wind exposed locations near treeline. This activity should taper later in the week.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Likely

Expected Size: 2 - 5

Loose Dry

Watch for sluffing in the top 30 cm of the snowpack in areas that are sheltered from the wind.

Aspects: All aspects.

Elevations: All elevations.

Likelihood: Likely

Expected Size: 1 - 3