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Avalanche Forecast

Dec 31st, 2016–Jan 1st, 2017
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
1: Low
The avalanche danger rating below treeline will be low
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
1: Low
The avalanche danger rating below treeline will be low
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
1: Low
The avalanche danger rating below treeline will be low

Regions: North Columbia.

Watch for signs of reverse loading as the wind switches directions. Recent loading has also potentially awakened persistent weak layers, so conservative terrain selection remains critical.

Confidence

High - The weather pattern is stable

Weather Forecast

SUNDAY: A mix of sun and cloud, 20-40 km/h northeast winds, alpine temperatures around -16.MONDAY: Sunny with cloudy periods, 10-20 km/h east winds, alpine temperatures around -20.TUESDAY: Sunny with cloudy periods, 20-30 km/h east winds, alpine temperatures around -13.

Avalanche Summary

Widespread storm slab activity was reported on Friday including natural and explosive triggered avalanches typically in the size 2-2.5 range, with some larger avalanches in extreme terrain. A few cases of storm slabs stepping down to the mid-December interface were reported on steep south-facing slopes and on wind-loaded features. A fatal avalanche occurred in the Clemina area of the North Monashees. The avalanche was triggered by a rider on a wind-loaded feature, and potentially released on the mid-December interface. On Sunday, expect the recent storm snow to be most reactive in wind exposed terrain where moderate winds are forming fresh storm slabs. Triggering persistent slab avalanches remains possible in thin snowpack areas in the northern and eastern parts of the region.

Snowpack Summary

Between 50 and 100 cm of new low density snow has fallen over the past week, with the greatest accumulations in the Monashees. Shifting winds with moderate speeds are forming touchy storm slabs in exposed high elevation terrain. The mid-December interface can be found buried 80-120 cm deep and consists of faceted (sugary) crystals and/or surface hoar. There remains to be some uncertainty on the distribution and reactivity of this layer. Some recent patterns suggest the layer may be more reactive on steep south facing slopes and in areas with thinner snowpacks such as the eastern and northern parts of the region. The lower snowpack is well consolidated and features a thick rain crust near the ground.

Avalanche Problems

Wind Slabs

The recent storm snow is being redistributed by moderate winds to form touchy wind slabs at higher elevations. If triggered, wind slabs may step down to the mid-December persistent weak layer.
Use caution on open slopes and convex rolls If triggered the wind slabs may step down to deeper layers resulting in large avalanches.Use ridges or ribs to avoid pockets of wind loaded snow.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Likely

Expected Size: 1 - 2

Persistent Slabs

A weak layer buried in mid-December has produced large avalanches. Triggering this layer is more probably in parts of the region with thinner snowpacks like the north Monashees and east Selkriks.
Dig down to find and test weak layers before committing to a line.Be aware of the potential for large avalanches due to the presence of buried persistent weak layersAvoid steep convexities or areas with a thin or variable snowpack.

Aspects: All aspects.

Elevations: All elevations.

Likelihood: Possible

Expected Size: 2 - 3