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Avalanche Forecast

Jan 18th, 2019–Jan 19th, 2019
Alpine
3: Considerable
The avalanche danger rating in the alpine will be considerable
Treeline
3: Considerable
The avalanche danger rating at treeline will be considerable
Below Treeline
2: Moderate
The avalanche danger rating below treeline will be moderate
Alpine
3: Considerable
The avalanche danger rating in the alpine will be considerable
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: Lizard-Flathead.

Storm slabs are gradually building above a touchy weak layer. Be extra cautious around steep rolls and wind loaded slopes.

Confidence

Moderate - Forecast snowfall amounts are uncertain

Weather Forecast

FRIDAY NIGHT: 5-10 cm of snow, moderate southwest wind, alpine temperatures drop to -5 C.SATURDAY: Scattered flurries with another 5-10 cm of snow, strong southwest wind, freezing level climbing to 1300 m, alpine high temperatures around -3 C.SUNDAY: Mostly cloudy with flurries possible later in the day, strong west wind easing throughout the day, freezing level climbing to 1000 m, alpine high temperatures around -6 C.MONDAY: Skies clearing throughout the day, light to moderate north wind, alpine high temperatures around -6 C.

Avalanche Summary

Small slab avalanches were reported in the top 10-15 cm of new snow on Friday and Thursday. Slab avalanches will become more likely as snow accumulates above the freshly buried weak layer. The key is watching for signs of this new slab becoming reactive, such as cracking, whumpfing, or stiffer deeper pockets of snow.Two large snowmobile triggered avalanches were reported last weekend. 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

By Saturday, 15-25 cm of snow will have buried a layer of 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.

Avalanche Problems

Storm Slabs

New snow is gradually accumulating above weak surface hoar and/or crusts. Touchy slabs can be expected in areas with more than 20 cm of new snow, such as wind loaded slopes.
Watch for signs of instability such as whumpfing, or cracking. Avoid shallow rocky areas where triggering deeper layers is more likely.Be careful with wind loaded pockets, especially near ridge crests and roll-overs.

Aspects: All aspects.

Elevations: All elevations.

Likelihood: Likely - Very Likely

Expected Size: 1 - 2