South Coast

New snow and wind will add to the size and reactivity of recently formed storm slabs. Tricky conditions are expected on Saturday and conservative terrain selection is critical.

Moderate - Timing, track, or intensity of incoming weather system is uncertain

The first in a series of storm systems will reach the region on Friday evening. 10-20cm of new snow is expected between Friday evening and Saturday evening. Freezing levels are expected to climb to around 1300m and winds are forecast to be moderate to strong from the southwest. The second storm system is expected to reach the region on Sunday and is forecast to bring another 10-20cm by Monday night. Freezing levels are expected to hover around 1200m and alpine winds should remain moderate to strong from the southwest. A bit of a break between storm systems is currently forecast for Monday with another storm pulse Monday night.

On Wednesday, natural soft slab avalanches were reported up to size 2. This includes one size 2 from a north aspect at treeline and several size 1-1.5 on southerly aspects below treeline. Explosives triggered several more storm slab avalanches up to size 1.5. All these avalanches were reported to be releasing on the early January surface hoar layers. On Thursday, no new slab avalanches were reported but one natural cornice release was observed. This was a size 2 cornice release from a north aspect at 2300m elevation. The cornice entrained loose snow but did not trigger a slab. Natural and human-triggered avalanches are expected to increase in size and reactivity as the storm progresses over the weekend.

The new snow will add to the storm slabs which formed earlier in the week. The previous snowfall was highly variable across the region. Northwest of Pemberton up to 40cm of snow fell. Further inland the storm only brought between 15 and 25cm to the Duffy and Coquihalla. This snow is now settling into a soft slab that overlies a crust on steep solar aspects, or a layer of surface hoar on sheltered and shady slopes at all elevations. Moderate to strong southwest through southeast winds have been loading lee features at treeline and in the alpine. 10-15 cm deeper is a second buried weak layer again consisting of a melt-freeze crust on solar aspects in the alpine or well-developed surface hoar in sheltered areas at treeline and lower elevations. The mid and lower snowpack is generally strong, with the exception of shallow snowpack areas that may be more faceted. At lower elevations below treeline recent rain may have saturated the upper snowpack.