Archived

Avalanche Forecast

Nov 20th, 2011–Nov 21st, 2011

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

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: Kootenay Boundary.

This bulletin is based on limited data. Local variation in conditions and danger levels are likely to exist. To produce more accurate forecasts, we need information. Please send an email to [email protected].

Confidence

Poor - Due to limited field observations

Weather Forecast

A strong Pacific System arrives on shore Monday, bringing heavy precipitation to the South Coast before moving inland late in the day. Monday: Expect clouds to build and winds to turn southwesterly. Flurries likely to begin late in the day and winds will increase. Temperatures will climb to -5. Tuesday: Snow, at times heavy. Winds continue up to 80km/h from the southwest and freezing levels could climb as high as 1800m. There is a chance of freezing rain at lower elevations. Wednesday: Snow continues, tapering late in the day. There will be significant differences in new snow amounts from west to east across the region, with the western upslopes receiving much more snow. I would not be surprised if these areas received 40-50cm of new snow from this system.

Avalanche Summary

Observations are extremely limited at this time. No new avalanches have been reported.

Snowpack Summary

10-30cm of new snow has fallen in the last 48hrs, with significantly more at the south end of the region. Snowpack depths are likely in the 60-80cm range at about 1600m and about 125cms at 2000m. In the upper snowpack, windslab and storm snow instabilities exist around lee features and ridgelines. There are also reports of a thin rain crust in the upper 50cm. Watch for the possibility of reverse loading with the recent Easterly winds.

Avalanche Problems

Wind Slabs

Strong southwesterly winds will build fresh windslabs in lee features and around gullies. Be locally aware of how much new snow is falling and how the wind is affecting the snow. Don't forget that old windslabs may still be lurking.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Possible - Likely

Expected Size: 1 - 3