Avalanche Forecast

Issued: Dec 30th, 2016 5:18PM

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

shorton, Avalanche Canada

North Columbia.

Slab avalanches in steep terrain are still likely following the recent large storm, especially in wind-affected terrain. Conservative terrain choices are recommended.

Summary

Confidence

Moderate - Wind speed and direction is uncertain

Weather Forecast

SATURDAY: Flurries with accumulations of 5-15 cm, light to moderate northwest winds, alpine temperatures around -12.SUNDAY: A mix of sun and cloud, light northeast winds, alpine temperatures around -16.MONDAY: Sunny with cloudy periods, light northeast winds, alpine temperatures around -20.

Avalanche Summary

Widespread storm slab activity was reported on Friday including natural and explosive triggered avalanches typically in the size 2-2.5 range.Expect storm slab activity to continue into the weekend and be extra touchy in wind affected terrain. 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. Recent tests suggest the the new snow is well bonded to the interface in most areas, but remains a concern in thin snowpack areas 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.

Problems

Storm Slabs

Lots of new snow has piled up over the past week and will gradually settle into a storm slab. Watch for signs like shooting cracks to alert you to slab formation and be especially wary around areas exposed to the wind.

Avoid areas with overhead hazard.Shooting cracks and recent avalanches are both strong indicators of unstable snowpack.Choose conservative lines and watch for clues of instability.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

2 - 3

Persistent Slabs

A weak layer buried in mid-December has produced large avalanches. Spotty patches of surface hoar have made it difficult to pinpoint where this layer might react. Thin snowpack areas in the north and east parts of the region are the most likely.

Be aware of the potential for large avalanches due to the presence of buried persistent weak layersDig down to find and test weak layers before committing to a line.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

2 - 3

Valid until: Dec 31st, 2016 2:00PM