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Avalanche Forecast

Dec 29th, 2014–Dec 30th, 2014
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
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: Sea To Sky.

Watch for fresh wind slabs in unusual locations.

Confidence

Fair

Weather Forecast

Synopsis: Arctic air to dominate for a few days, then warming from the north. Outflow winds should reach their peak Tuesday morning. By Tuesday afternoon warmer Pacific air associated with the offshore upper ridge should move inland opening the door to a potential inversion or an above freezing layer between 1500 & 2500m.Tuesday: Freezing Level: Valley Bottom; Precipitation: Nil; Wind: Treeline: Light, NW | Ridgetop: Strong, NE.Wednesday: Freezing Level: Valley Bottom, potential AFL 1500 2500m; Precipitation: Nil; Wind: Treeline: Light, NE | Ridgetop: Light, N/NW.Thursday: Freezing Level: Valley Bottom, potential AFL 1500 2500m; Precipitation: Nil; Wind: Treeline: Light, NW | Ridgetop: Light, NW.

Avalanche Summary

On Friday a few size 1-1.5 wind slabs failed in steep terrain. On Wednesday, a snowboarder triggered a size 2-2.5 slab on a north aspect at 1900 m in the Callahan area. The crown was 10cm-100cm deep. The slab is believed to have failed on a crust. The snowboarder was buried, but was recovered safely by companion rescue.

Snowpack Summary

10-20 cm of recent snow is likely being shifted into thin, fresh and sensitive wind slabs on lee terrain features. The recent snow overlies variable surfaces including large surface hoar crystals, old wind slabs and wind-scoured surfaces. A deeper layer of surface hoar buried in mid-December (now down 40-70cm) has been gradually gaining strength, but may still be a concern in some areas. The mid and lower snowpack contain several old crust layers, one of which may have been the failure layer for a recent burial (see avalanche summary).

Avalanche Problems

Wind Slabs

Modified outflow winds are likely forming recent storm snow into fresh sensitive wind slabs in unusual locations at and above treeline.
Avoid open slopes and convex rolls at and below treeline where buried surface hoar may be preserved.>Travel on ridgetops to avoid wind slabs on slopes below.>Avoid travelling in areas that have been reverse loaded by winds.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Possible - Likely

Expected Size: 1 - 3