Avalanche Forecast

Arctic air maintains cold and clear conditions across the Columbias.

Monday night: Partly cloudy. No significant precipitation. Light southwest wind at 2000m, moderate northwest upper level winds. Alpine temperatures around -25 C.

Tuesday Partly cloudy with isolated flurries. Light southwest wind at 2000m, moderate northwest upper level winds. Alpine high -24 C.

Wednesday: Partly cloudy. Light southwest wind at 2000m, strong northwest upper level winds. Alpine high -25 C.

Thursday: Flurries bringing around 5 cm overnight then clearing. Light southwest wind at 2000m, moderate northwest upper level winds. Alpine high of -22 C.

Natural and human triggered wind slabs up to size 1.5 have been reported over the last few days.

The persistent slab problem continues to produce sporadic events on the early December crust/facet layer. A skier triggered size 2.5 was reported in the Monashees near Revelstoke on Sunday. This avalanche problem is challenging to forecast and is best managed by conservative terrain management. 

If you head into the mountains, please submit your findings and photos to the Mountain Information Network!

40-60 cm of fresh storm snow has accumulated over the past week. In the alpine and exposed treeline elevations it has been redistributed into deeper deposits in wind loaded features. In the southern parts of the region, winds have been consistent from the southwest. In the north, southwest winds came in with the snow and were followed by a northerly blast, resulting in atypical loading patterns and wind slabs on all aspects. 

At lower elevations the settling storm snow may sit over a weak surface hoar layer, which is creating slabs that are reactive to human triggers. The surface hoar is most likely to be found on sheltered slopes at treeline and below.

The crust formed by the early December rain event sits 100-150cm deep and is found up to 2200m in the North Columbias. In areas where the crust is buried deeper than one meter, it has begun to decompose and shows limited reactivity. In many areas, the snow above is well bonded to the crust. However in some areas around treeline and below, weak faceted grains have been observed above this crust - creating a weak interface that has proven to remain reactive to human triggers.

• Recent wind has varied in direction so watch for wind slabs on all aspects.
• Be careful with wind loaded pockets, especially near ridge crests and roll-overs.
• Be aware of the potential for large avalanches due to the presence of a persistent slab.