Avalanche Forecast

We are entering a period of clear and cool weather.

TUESDAY NIGHT: Partly cloudy, light northwest wind, freezing level dropping to valley bottom and alpine temperatures drop to -10 C.

WEDNESDAY: Mostly cloudy, light west wind, alpine high temperatures around -5 C.

THURSDAY: Mix of sun and cloud, light wind, alpine high temperatures around -8 C.

FRIDAY: Mostly cloudy, light wind, alpine high temperatures around -8 C.

As the weather clears we are uncertain about how quickly the recent snow will gain strength and bond to old interfaces. It likely sits atop a weak layer of surface hoar in wind-sheltered areas at treeline and at upper below treeline elevations (above the extent of the rain crust). At higher wind-affected areas it has likely formed thicker wind slabs.

With little in terms of field observations, a cautious and conservative approach to terrain is needed. Be aware of these new avalanche problems by looking for signs of instability like shooting cracks and whumpfs. Furthermore, an avalanche triggered in the upper snowpack could cause a larger deep persistent slab avalanche.

Our eyes and ears in the mountains are limited this winter due to fewer professional observations. If you go out in the mountains, please share your observations on the Mountain Information Network (MIN).

Monday's storm delivered variable amounts of snow to the Cariboos with roughly 30 cm around Blue River and Valemount, 10 cm in the Robson Valley, and 5 cm around Barkerville. This new snow sits on top of a melt-freeze crust on south aspects and widespread surface hoar at treeline and below. Generally speaking, new snow does not bond well to these types of surfaces and will create a problem moving forward. Freezing levels were around 1300 m during the storm, so lower elevations are rain soaked and will form a crust on the surface.

A recent MIN report from the Barkerville area found a weak layer 30 cm below the surface. The lower snowpack is characterized by a couple of crusts, the most notable of which is sitting near the base of the snowpack, surrounded by a weak layer of sugary facets. It is most likely to be reactive to human triggers on south facing slopes and in shallow, rocky areas in the alpine.

• Choose conservative terrain and watch for clues of instability.
• Potential for wide propagation exists, fresh slabs may rest on surface hoar, facets and/or crust.
• 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 deep persistent slab.