Archived

Avalanche Forecast

Nov 18th, 2011–Nov 19th, 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

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

Regions: Northwest Coastal.

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

Drier and colder conditions are forecast for Saturday. Strong easterly winds may occur in the bigger valleys as cold air flows out to the sea. The next storm is expected to hit the north coast as early as Sunday noon. Expect strong winds and heavy precipitation Sunday night and Monday. The freezing levels should rise to near 1000 metres with the new storm.

Avalanche Summary

I suspect there was a decent natural cycle during the storms earlier this week, especially on wind-loaded slopes. The possibility of human-triggered wind and storm slab avalanches is expected to remain for the forecast period.

Snowpack Summary

Another 10-15cm adds to the recent storm snow totals. Varying temperature, precipitation intensity, and wind throughout the recent storms have probably resulted in weaknesses strewn throughout the top metre or so. However, the relatively warm post-storm temperatures on Thursday should favor settlement and strengthening. The mid and lower snowpack is generally well settled and strong, with an old rain crust near the ground. Strong outflow winds from the east may build new wind-slabs on westerly aspects in areas that have snow available for transport.

Avalanche Problems

Wind Slabs

Near ridgecrests and terrain breaks, and in cross-loaded gullies.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Possible - Likely

Expected Size: 2 - 5

Storm Slabs

Steep unsupported slopes.

Aspects: All aspects.

Elevations: All elevations.

Likelihood: Possible - Likely

Expected Size: 1 - 4