Avalanche Forecast

Issued: Jan 6th, 2017 4:40PM

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

mgrist, Avalanche Canada

Lizard-Flathead.

Be cautious near shallow rocky areas, where a small slab could trigger buried weak layers resulting in large avalanches. Minimize your exposure to overhead hazard, especially on north-facing slopes.

Summary

Confidence

Moderate - Due to the number of field observations

Weather Forecast

We've had a bit of a shift from the very cold conditions, and temperatures have warmed by 5 - 10 degrees Celcius. Only some isolated flurries are possible until late Sunday, when a small amount (5-10 cms) of light dry snow is forecast.SATURDAY: Sunny breaks with increasing clouds overnight. Flurries overnight with little accumulation. Winds light southerly. Alpine highs to -13 Celcius.SUNDAY: Mainly cloudy. Winds light southerly. Alpine temperatures between -15 and -20 Celcius; 5-10 cms light dry snow overnight.MONDAY: An additional 5-10 cms light dry snow are possible during the day and overnight. Winds light - moderate southwesterly. Alpine temperatures steady near -14 to -18 Celcius.

Avalanche Summary

A spooky size 3 natural avalanche was spotted in the Liverwurst bowl on a north aspect at 1800m - see today's MIN report at avalanche.ca. The crown is approximately 150cms high and the failure may have been on basal facets, which are large, sugary and weak. A skier triggered size 2 wind slab was reported near Fernie, east aspect also at 1800m.

Snowpack Summary

We're seeing surface snow conditions ranging from very wind affected (sastrugi and hard slabs) to softer wind slabs. The best skiing seems to be on north-facing aspects (but please see the avalanche summary (and MIN report) above and minimize your overhead exposure). These sit on a variety of older wind-affected surfaces at treeline and in the alpine and have given easy test results in the top 15-20cms of the snowpack.That said, the main concern remains the windslabs (and some cornices) formed in the alpine thanks to the recent arctic outbreak winds. Deeper in the snowpack the mid-December persistent layer (facet interface) has been more prominent and reactive in the Corbin zone than closer to Fernie: Watch out for thinner snow packs and areas of crossloading in isolated areas (think shallow rocky areas) where an avalanche could step down to trigger deeper layers.

Problems

Wind Slabs

Variable northerly winds have created reactive wind slabs in exposed lee terrain. In shallow snowpack areas, these slabs could pull out to deeper layers below, increasing the size of an avalanche.

If triggered the wind slabs may step down to deeper layers resulting in large avalanches.Be cautious as you transition into wind affected terrain.Avoid travelling in areas that have been reverse loaded by winds.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

1 - 2

Persistent Slabs

Where denser snow overlies weak, sugary snow, there is the potential to trigger large, dangerous avalanches. Dig down and test for weak layers before committing to any steep slope.

Be aware of the potential for full depth avalanches due to deeply buried weak layers.Danger spots are where denser snow overlies weak, sugary snow below.Watch for whumpfing, hollow sounds, shooting cracks or recent avalanches.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

2 - 3

Valid until: Jan 7th, 2017 2:00PM