Avalanche Forecast

Issued: Feb 11th, 2015 7:28AM

The alpine rating is considerable, the treeline rating is considerable, and the below treeline rating is moderate. Known problems include Persistent Slabs, Wind Slabs and Loose Wet.

rbuhler, Avalanche Canada

South Columbia.

The persistent slab will remain extra sensitive due to the unseasonably warm temperatures. Conservative decision-making remains important, especially in the alpine. If the sun comes out, use extra caution on south-facing slopes.

Summary

Confidence

Fair - Timing or intensity of solar radiation is uncertain

Weather Forecast

Light scattered precipitation is expected Wednesday overnight with freezing levels around 1500m and strong alpine winds from the SW-W. Thursday is forecast to be mainly dry and mostly cloudy but sunny breaks are possible. Freezing levels should be around 2000m and alpine winds light-to-moderate from the SW. Light scattered precipitation is possible Thursday overnight. Friday should see dry conditions with a mix of sun and cloud. Freezing levels should spike on Friday to around 3000m. On Saturday, freezing levels should fall back below 2000m and this should be the start of a cooling trend heading into next week. 3-6mm of precipitation are currently forecast for Friday overnight and Saturday with strong alpine winds.

Avalanche Summary

A widespread avalanche cycle occurred on Friday through Monday during the storm. Activity tapered off on Tuesday but isolated natural avalanches to size 2.5 were reported. Explosives also produced slab avalanches and loose wet results. On Thursday, natural activity is generally not expected but is possible on steep south-facing slopes if the sun comes out. Human-triggering of the persistent slab remains possible, especially on steep slopes and wind loaded features in the alpine. If new wind slabs form overnight Wednesday, they may be touchy on Thursday.

Snowpack Summary

At higher elevations, 60-100cm of rapidly settling snow sits over the late-Jan crust/surface hoar layer. Rain has recently soaked the snow surface up to around 1900m and moist snow is reported to at least 2200m. Overnight cooling may be forming a weak surface crust at some elevations. Strong SW winds had formed wind slabs in exposed leeward terrain features. New wind slabs may form in the alpine with the forecast strong winds from the SW-W. The mid-January surface hoar is typically down 80-120cm and has been recently reactive in many areas. The mid-December weak layer is down around 1.5m but was generally unreactive through the storm.

Problems

Persistent Slabs

The late-Jan and mid-Jan layers have both been reactive recently. Human-triggering is still possible and both these layers remain a real concern, especially in the alpine. A cornice fall or small avalanche could easily step-down to these layers.

Be aware of thin areas that may propagate to deeper instabilities.>Be aware of the potential for large, deep avalanches due to the presence of buried surface hoar.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

3 - 6

Wind Slabs

Strong forecast winds may form new wind slabs in exposed alpine terrain.

Be cautious as you transition into wind affected terrain.>Avoid freshly wind loaded features.>

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

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 3

Loose Wet

Loose wet avalanches are possible from steep terrain features where the snow surface is moist. If the sun comes out, sluffing from steep sun exposed slopes is possible.

Be cautious of sluffing in steep terrain.>Avoid sun exposed slopes when the solar radiation is strong, especially if snow is moist or wet.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 3

Valid until: Feb 12th, 2015 2:00PM