Northwest Coastal

Keep terrain choices conservative and minimize exposure to avalanche terrain during heavy precipitation and wind. Danger will increase over the day, as storm slabs continue to build.

In localised areas near Kitimat that see 40 cm of new snow by midday Monday, danger is HIGH. 

SUNDAY NIGHT: Cloudy with snow beginning early evening, 10 cm expected in most areas, and up to 30 cm possible near Kitimat. Strong to extreme southwest winds. Freezing levels around 1000m. 

MONDAY: Snow continues with another 10-15 cm possible over the day, Kitimat may again see around 30 cm. Freezing levels around 1000 m. Alpine high -2. Strong southwest winds. 

TUESDAY: 10-20 cm possible by Tuesday morning. Light snowfall continues throughout the day, with around 10 cm possible. Moderate to strong southwest winds. Freezing levels around 1000 m, alpine high of -2. 

WEDNESDAY: 5 cm expected over the day with cloudy skies. Moderate to strong southwest winds. Freezing levels around 1000 m, alpine high -1.

On Saturday storm snow was reactive to human and natural triggers. Slab avalanches were reported mainly in north and east facing terrain (lee to the southwest winds) to size 2.5. Check out this MIN report for a great description of post-storm conditions near Shames. 

Of note, two remotely triggered avalanches were reported. One within the storm snow and one on the buried surface hoar/crust layer from late February. Activity on persistent weak layers has been limited throughout the storm. Avalanches are unlikely to be human triggered on these layers, but possible with a large trigger such as a storm slab in motion or a large cornice fall.

Reports also indicated the effects of brief periods of sun on the snowpack, with small wet avalanches produced on steep sun affected slopes. Rising freezing levels produced small avalanches on all aspects below 1000 m. 

With another storm approaching with similar conditions - we expect to see similar human triggered and natural avalanche activity throughout Monday and Tuesday.

By Monday morning, 10-20 cm of new is expected to fall over a crust on south facing (and sun affected slopes). On other aspects, snow will sit on the settling storm snow that fell over the weekend. Strong southwest winds are expected to create deeper deposits on east facing slopes at higher elevations. Low elevations likely hold 10-20 cm of wet/moist snow sitting over a widespread crust on all aspects below 1000 m.

On south facing slopes a crust sits 30-50 cm deep, with surface hoar above in isolated sheltered terrain features. Other aspects hold more hard wind pressed snow below the recent storm snow.

A surface hoar and crust layer buried in late February showed some reactivity during the weekends storm. It is most prominent in sheltered terrain features at treeline elevations. 

A thick crust from mid-February is buried 70-110 cm. The snowpack below is well consolidated.

• Minimize exposure during periods of heavy loading from new snow, wind or rain.
• As the storm slab problem gets trickier, the easy solution is to choose more conservative terrain.
• Storm slabs in motion may step down to deeper layers resulting in large avalanches.
• Conditions are expected to deteriorate throughout the day.