Avalanche Forecast

Issued: Jan 10th, 2017 5:00PM

The alpine rating is moderate, the treeline rating is moderate, and the below treeline rating is low. Known problems include Wind Slabs.

Avalanche Canada mgrist, Avalanche Canada

Watch for new wind slabs and pockets of soft slabs at higher elevations.

Summary

Confidence

Moderate - Due to the number of field observations

Weather Forecast

Cold and clear for a few days. The next weather system arrives late Saturday. WEDNESDAY: Sunny. Light northeasterly winds (15-25Km/hr). Freezing level at valley bottom. Alpine high temperatures near -15 Celcius.THURSDAY: Sunny. Light southwesterly winds 10-20 Km/hr. Freezing level at valley bottom. Alpine high temperatures around -12 Celcius. FRIDAY: Sunny with a chance of flurries in the afternoon. Lightly southwesterly winds 10-20 Km/hr. Freezing level at valley bottom. Alpine high temperatures to -11 Celcius.

Avalanche Summary

On Saturday, skiers triggered a Size 2 wind slab near treeline on Zupjok peak (Coquihalla area). The culprit was northeasterly outflow winds loading southwest aspects. See the MIN post for more details:http://www.avalanche.ca/map/forecasts/south-coast-inland?panel=mountain-information-network-submissions%2Fd9620fad-38ad-4b09-adb2-e38941dbd6d4No new natural avalanches observed.

Snowpack Summary

Lingering soft slabs and wind slabs are the primary weaknesses of concern in the snowpack. 25-30cm of low density snow fell Sunday/Monday in the southern (Coquihalla) area, while northern sections received 7-15cms of new snow. Moderate southwesterly winds redistributed the new snow onto north (east) aspects forming reactive soft slabs. Winds shifted Tuesday to classic outflow (northerly) patterns with moderate winds at ridge top. This pattern has resulted in some 'reverse loading' of southerly slopes and creating wind slabs. Previous cold temperatures from last week and strong winds left our snow surface a mix of soft wind slabs, hard wind slabs, sastrugi, faceted snow, and even some surface hoar. These older wind slabs (on south - west aspects) remain a concern in our current snowpack and were triggered by skiers on Saturday (see link above).

Problems

Wind Slabs

An icon showing Wind Slabs
The recent snow buried old stubborn wind slabs (on SW aspects), and formed new wind slabs in the lee of exposed terrain (NE aspects). Watch out for wind loaded pockets where reactive wind slabs may still be lingering.
Carefully evaluate steep lines for wind slabs.Watch for areas of hard wind slab in steep alpine features.Choose well supported terrain and avoid convexities.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Valid until: Jan 11th, 2017 2:00PM

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