Northwest Inland

The parade of storms is adding incremental strain to deeper weak layers at the same time surface avalanches threaten to step down to them. Forecast snowfall is uncertain and variable over the region, so make observations as you travel and adjust accordingly.

Friday night: Cloudy with flurries bringing 10-15 cm of new snow. Moderate to strong southwest winds.

Saturday: Cloudy with continuing flurries bringing a variable 5-20 cm of new snow, easing overnight. strong to extreme west winds, easing overnight. Alpine high temperatures around -11.

Sunday: Mainly cloudy with isolated flurries and a trace of new snow. Light west or southwest winds, increasing a bit overnight. Alpine high temperatures around -11.

Monday: Mainly cloudy. Light to moderate west winds, easing over the day. Alpine high temperatures around -11.

Reports from Thursday's storm showed an uptick in avalanche activity brought on by new snow and wind. Observations were limited, but one large (size 2) natural wind slab was reported in the Kispiox area while more numerous dry loose releases and larger audible avalanches were seen and heard further west in the Howsons. More widespread natural storm slab activity was observed in our neighbouring Northwest Coastal region.

Another recent large (size 2.5) persistent slab avalanche, triggered by a large snow machine, was observed in the Kispiox area on Tuesday, this time failing on a southeast-facing slope at about 1600 metres. No new avalanches were reported on Wednesday.

Since February 3rd there have been many very large and destructive avalanches failing on deeply buried surface hoar and crust/facet layers near the bottom of the snowpack. The bulk of the activity has been above treeline on north through east facing aspects, but large alpine slopes that have not yet avalanched should be treated as suspect. A few examples of the most recent activity are reported here:

Feb 9: Very large avalanche on the Kathlyn Face near Smithers. Details/Photos here and here.

Feb 9: Large avalanche in the French Peak Complex. Details/Photos here.

Feb 9: Very large avalanche near the Pine Creek Trail. Details/Photos here.

Feb 8: Large snowmobile triggered avalanche in the Babines. Details/Photos here.

Feb 8: Very large avalanche on Mt. Elmstead above Silver King Basin Trail in the Babines. Details/Photos here.

A variable 15-35 cm of new snow is expected to accumulate in the region by the end of the day Saturday, bringing snow totals for the week to a similarly variable 25-60 cm. With consistently elevated recent winds, each layer of recent snow has buried mainly wind-affected surfaces in exposed areas before subsequently being redistributed and affected by wind itself. In more sheltered areas, the recent snow collectively overlies overlies crusts that can be found up to roughly 1200 m as well as on open south-facing slopes. 

Recently, the above-mentioned pattern of wind redistribution onto specific slopes appeared to push our region's persistent weak layers to their breaking point.

A weak layer of faceted snow that formed during cold weather in mid January is one likely failure plane responsible for the recent rash of large avalanches in the region. Depending on location this layer may be composed of soft facets, surface hoar, or both. It is buried approximately 60-120 cm below the surface. As a product of previous widespread cold temperatures, the faceted snow associated with this layer exists all over the region, however it may be bridged over by a firm crust at lower elevations.

An older Crust/facet layer from November, lurking at the base of the snowpack, is the more widely observed culprit in recent persistent slab activity, having produced many very large avalanches since February 3rd. As a product of old, weak snow from the early season, this layer is most likely to be found at high elevations.

The most recent activity with these deeper snowpack layers has been around Smithers, Hazelton, Kispiox and the Babines, but it should be assumed that they are widespread problems.

• Storm snow and wind is forming touchy slabs. Use caution in lee areas in the alpine and treeline.
• Storm slabs in motion may step down to deeply buried weak layers resulting in very large avalanches.
• Avoid thin areas like rock outcroppings where you're most likely to trigger avalanches failing on deep weak layers.