Avalanche Forecast

Moderate - Forecast snowfall amounts are uncertain.

Monday night: Cloudy with flurries bringing 5-15 cm of new snow, focused to the west of the region. Moderate to strong southwest winds, strongest in the west of the region and increasing into the morning.

Tuesday: Cloudy with continuing flurries bringing 10-20 cm of new snow, again focused to the west, easing in the afternoon. Snowfall increasing again overnight. Moderate to strong southwest winds (strongest in the west), easing late afternoon before increasing again overnight. Alpine high temperatures around -4 with freezing levels to about 1400 metres.

Wednesday: Mainly cloudy with easing flurries and a trace of new snow, 5-10 cm with overnight accumulations. Light to moderate west winds. Alpine high temperatures around -6 with freezing levels rising to 1200 metres.

Thursday: Mainly cloudy. Light west winds. Alpine high temperatures around -9.

Saturday's reports, still hindered by visibility, gave a bit more evidence of the recent natural avalanche cycle in the Howsons, including debris from a size 3 (very large) release and more widespread debris from size 2 (large) avalanches. Roadside observations of the east flank of Hudson Bay Mountain showed no new avalanches.

Notably, the movement of a large snow machine managed to remote trigger a very large (size 3.5) release in the Kispiox area. This avalanche failed on the deeply buried surface hoar layer from early January, with a crown fracture of 50-200 cm deep.

Reports from Friday gave initial evidence of a natural avalanche cycle was ongoing in areas like the Howsons where up to 100 cm of storm snow accumulated. Aerial observations between the Howsons and Smithers on Friday revealed significant natural activity in avalanche tracks and runouts in spite of limited visibility.

Looking forward

A variable 15-35 cm of new snow is expected to accumulate in the region by the end of the day on Tuesday, with the greatest accumulations confined to the far west of the region. The new snow will bury a mix of sheltered low density recent snow or more widespread wind-affected surfaces at higher elevations. It will add to 50 to 90 cm of recent storm snow.

The recent storm snow rests on a weak layer of facets that developed during the mid-January cold snap. Below treeline it rests on a melt-freeze crust and a well settled snowpack.

In most areas of the region, the early January surface hoar layer, now buried 150-200 cm deep, is considered dormant. It remains a more active concern in the Kispiox area and further north. Recent activity on this layer, although isolated, is noted in our avalanche summary.

A deep crust/facet layer lurks at the base of the snowpack, especially in shallower (eastern) areas that was reactive earlier in January. While it is promising that last week's snowfall did not trigger avalanches on this layer, there is some uncertainty about the possibility for avalanches in surface layers to step down to it. Triggering this layer is most likely in shallow, rocky start zones or with a large load such as cornice failure or avalanche.

• Storm slabs in motion may step down to deeper layers resulting in large avalanches.
• Make observations and assess conditions continually as you travel.
• Watch for avalanche hazard to increase throughout the day.
• Storm snow and wind is forming touchy slabs. Use caution in lee areas in the alpine and treeline.