Northwest Coastal

Thick storm slabs have accumulated in the wake of a coastal storm. Sustained winds will keep conditions touchy on Monday.

Moderate -

Monday: Mainly cloudy with no new snow. Winds moderate to strong from the northwest. Freezing level to 300 metres with alpine temperatures of -7. Tuesday: Sunny with cloudy periods. Winds light to moderate from the northeast. Freezing level returning to valley bottom with alpine temperatures of -8. Wednesday: Sunny. Winds light to moderate from the northeast. Alpine temperatures to -8 with a possible temperature inversion bringing temperatures closer to -4.

Although the storm obscured visibility of most higher elevation terrain, a number of observations of a natural avalanche cycle took place from lower elevations on Saturday. Alpine and treeline features were observed running to Size 3.5 while warm and quickly consolidating storm snow below treeline promoted both storm slab and glide avalanche activity to Size 2. Numerous loose wet avalanches have also been reported at highway elevations over the past two days. It remains to be seen to what extent avalanche activity has involved deeper persistent weaknesses, but at least two larger (Size 3-3.5) avalanches were reported failing at ground level up in the Ningunsaw area. Sustained strong winds and a changing wind direction can be expected to promote ongoing natural avalanche activity over the short term.

A storm that impacted the region over Friday to Sunday morning has delivered approximately 60-110 cm of new snow to the mountains, with the greatest depths accumulating in coastal areas. Strong to extreme southwesterly winds accompanied the storm while lower elevations saw precipitation falling as rain. As of now we can expect anywhere from 70-130 cm to have accumulated above above the latest buried surface hoar layer from January 23rd. This surface hoar was previously reported growing up to size 10 mm at treeline and below and may be associated with a crust below 1100 metres. Although storm slab activity has captured our attention, there continue to be several other surface hoar layers of concern from early January and Christmas. Some reports have shown these persistent weak layers to be rounding and bonding, however recent reports have shown sudden planar releases in snowpack tests with hard forces applied. The heavy precipitation has been a good test for these older buried weak layers and observations over the next couple of days should reveal to what extent they have been involved in avalanche activity.