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Archived

Avalanche Forecast

Jan 10th, 2013–Jan 11th, 2013
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
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
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

Regions: Northwest Coastal.

Confidence

Good

Weather Forecast

Synopsis: A weak weather system could brush the coast on Friday resulting in more cloud and a chance of flurries. Areas further inland should still see some sunny breaks. Saturday and Sunday should see a mix of sun and cloud as a ridge of high pressure rebuilds off the coast. The freezing level should stay at valley bottom throughout the period. Winds should be generally light from the north, but areas closer to the coast could see stronger outflow winds develop.

Avalanche Summary

Clear weather on Wednesday revealed a previous natural avalanche cycle (+48 hours) with slabs up to size 3. Most events appeared to release within the recent storm snow, with a few events suspected to have stepped down to the late December surface hoar or facet layers.

Snowpack Summary

50-100cm of storm snow has fallen in the past 10 days or so. Northerly outflow winds may have produced wind slabs in exposed terrain primarily near the coast. Weaknesses within this recent storm snow have strengthened but a weak layer of facets or surface hoar exists at the base of the storm snow. Recent snowpack tests give generally moderate sudden planar, or "pops", results on this buried surface hoar layer and indicate potential for wide propagation. Near the base of the snowpack, a crust/facet layer continues to concern local avalanche professionals. This weakness is unlikely to be triggered by a single person, but it remains possible with a very heavy load (e.g. cornice fall) or from a thin-spot trigger point.

Avalanche Problems

Persistent Slabs

A weak layer of surface hoar and/or facetted snow exists under the recent storm snow and has been susceptible to human triggering.
Choose well supported terrain without convexities.>Be aware of the potential for large, deep avalanches due to the presence of buried surface hoar.>Choose conservative lines and watch for clues of instability.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood: Possible

Expected Size: 2 - 5

Wind Slabs

Northerly outflow winds may create wind slabs in unusual places in exposed terrain at all elevations.
Avoid travelling in areas that have been reverse loaded by winds.>Be cautious as you transition into wind affected terrain.>

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

Elevations: All elevations.

Likelihood: Possible

Expected Size: 1 - 3