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Avalanche Forecast

Jan 11th, 2018–Jan 12th, 2018
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
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
3: Considerable
The avalanche danger rating below treeline will be considerable

Regions: Northwest Coastal.

Watch for touchy wind slabs at all elevations created from strong outflow winds.

Confidence

Moderate - Due to the number of field observations

Weather Forecast

FRIDAY: Increasing cloudiness over the day with light snowfall starting in the afternoon, accumulation 10-20 cm overnight, strong outflow winds, alpine temperature near -10 C, freezing level below valley bottom.SATURDAY: Cloudy with light snowfall, accumulation 5 to 10 cm, light to moderate southerly winds, alpine temperature rising to 0 C but cold in the valleys, freezing level near 1800 m with inversion conditions.SUNDAY: Cloudy with light precipitation, accumulation 5-10 mm, moderate southerly winds, alpine temperature near 4 C but possible cold air in the valleys, freezing level near 2000 m with inversion conditions.

Avalanche Summary

A small naturally triggered wind slab was observed on a southerly aspect on Thursday.  More avalanches are likely with continuing strong outflow winds.

Snowpack Summary

The snowpack is variable across the region. Wind slabs and storm slabs are found on some slopes in the alpine and at treeline.  Strong outflow winds have formed wind slabs on southerly and southwesterly lee features at all elevations.Up to 45 cm recent snow overlies several layers of interest in the upper snowpack. These include crusts, surface hoar and facets. A hard crust with associated facets from mid-December sits deeper in the snowpack, about 60 cm down. Any of these layers could create a persistent slab problem if new snow, wind-loading or warming change the properties of the slab above.The lower snowpack is generally strong, with the exception of areas around Stewart and further north where a basal crust and facets exist.

Avalanche Problems

Wind Slabs

Strong outflow winds have created stiff wind slabs.  Wind slabs formed from the last storm may also linger in lee features.  If triggered, these slabs may step down to buried weak layers and form large avalanches.
Avoid exposure to terrain traps where the consequences of a small avalanche could be serious.Travel on ridgetops to avoid wind slabs on slopes below.

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

Elevations: All elevations.

Likelihood: Possible - Likely

Expected Size: 1 - 2