Avalanche Forecast

Issued: Jan 17th, 2019 4:52PM

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

Avalanche Canada shorton, Avalanche Canada

The incoming snowfall is burying a new weak layer. On Friday, deeper wind loaded slopes may have enough new snow for avalanches on this layer.

Summary

Confidence

Moderate - Forecast snowfall amounts are uncertain

Weather Forecast

THURSDAY NIGHT: Light flurries with localized accumulations of 5-10 cm, moderate southwest wind, alpine temperatures drop to -13 C.FRIDAY: Isolated flurries with trace accumulations, strong west wind, alpine high temperatures around -6 C.SATURDAY: 10-15 cm of snow, strong southwest wind, freezing level climbing to 1300 m, alpine high temperatures around -4 C.SUNDAY: Mostly cloudy then clearing in the afternoon, strong west wind, alpine high temperatures around -6 C.

Avalanche Summary

By Thursday afternoon, skier traffic produced a few small (size 1) avalanches in the new snow.Otherwise, no notable avalanche activity has been reported since last weekend.On Saturday, two large snowmobile triggered avalanches were reported on the Mountain Information Network. One was triggered on a thin, rocky, southwest facing feature near ridgecrest north of Fernie (see here for report). The other was triggered on a wind affected south facing slope at treeline in the Corbin area (see here for report). Deep persistent slab activity this season has been most common in parts of the region with shallow snowpacks (e.g. near the continental divide) and on alpine features with thin variable snowpack depths.

Snowpack Summary

Although incoming snowfall amounts are on the lighter side, the snow is burying large surface hoar crystals and sun crusts. This will create the potential for fast moving sluffs and/or thin slab avalanches with wide propagations. The most suspect terrain features will be steep slopes and rolls below 2000 m (where the largest surface hoar exists) and steep south-facing slopes in the alpine (where sun crusts exist).In shallow snowpack areas, the base of the snowpack may still be composed of weak faceted grains. In deeper snowpack areas, the middle and lower portions of the snowpack are generally considered to be well-settled and strong.

Problems

Wind Slabs

An icon showing Wind Slabs
New snow is gradually accumulating above weak surface hoar and/or crusts. On Friday, wind loaded slopes may have enough snow above this layer for slab avalanches.
Be careful with wind loaded pockets, especially near ridge crests and roll-overs.Avoid shallow rocky areas where triggering deeper layers is more likely.Watch for signs of instability such as whumpfing, or cracking.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Valid until: Jan 18th, 2019 2:00PM

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