Avalanche Forecast

Moderate - Uncertainty is due to rapidly fluctuating freezing levels. Uncertainty is due to the timing or intensity of solar radiation and its effect on the snowpack.

A warm ridge of high pressure establishes itself over the region on Friday and is expected to bring sustained freezing levels around 3000 m with an inversion for the weekend. 

Thursday Night: Skies clearing overnight, light to moderate NW wind, freezing levels 1200-1400 m. 

Friday: Mainly sunny, light to moderate NW wind, freezing levels climbing to around 3000 m with an inversion. 

Saturday: A mix of sun and cloud, light NW wind, freezing levels around 3200 m with an inversion. 

Sunday: A mix of sun and cloud, light to moderate W wind, freezing levels around 3000 m dropping to around 2000 m by the end of the day. 

On Tuesday, explosives triggered three large cornices, none of which triggered slabs on the slopes below. Just north of the region on Tuesday, two human-triggered size 1-1.5 wind slabs were reported on NW-NE aspects at 1950 m. On Monday, a natural size 2 storm slab was reported on a SW aspect around 1800 m. 

At higher elevations, the recent storm snow has buried the widespread January 16 melt-freeze crust which extends to around 2100 m. There have also been some observations of surface hoar sitting on the crust north of Pemberton but this does not appear to be widespread. This surface hoar was observed on polar aspects at treeline and in the alpine. The most recent storm snow is expected to have formed reactive storm slabs in wind exposed high elevation terrain. Storm slabs may become more reactive and widespread on Friday as the recent storm snow settles rapidly with the warming. At lower elevations, the upper snowpack is moist or wet from the recent rain event. 

The depth of the early December crust/facet layer is highly variable through the region but appears to be typically down 100-200 cm. Some operators are showing the depth as low as 60 cm in shallow snowpack areas and as deep as 3 m in wind loaded terrain. The weak layer is most prominent between 1700 and 2100 m. The layer has been dormant recently but is a concern for the period of major warming and sun forecast for the weekend. The most likely place to trigger it would be in thin, rocky snowpack areas where it is shallowest. 

• Watch for changing conditions today, storm slabs may become increasingly reactive.
• Be alert to conditions that change with elevation and wind exposure.
• The likelihood of deep persistent slab avalanches will increase with each day of warm weather.
• The more the snow feels like a slurpy, the more likely loose wet avalanches will become.