Southwest winds may have developed wind slabs at higher elevations.
Keep an eye on conditions and be ready to change your plans as Sunday brings a change in the weather.
New snow and strong southwest winds are building deep pockets of fresh wind slabs on leeward slopes. Look for signs of instability especially as you transition into wind-affected terrain.
If you see more than 15 cm fall be cautious of storm slabs building as well.
A weak layer from late March is found down 50 cm and is responsible for a number of recent human triggered and natural avalanches in the region. With incremental loading through the next few days watch for signs that this layer may be becoming more reactive in the terrain around you.
A weak layer of facets exists near the base of the snowpack. The likelihood of human triggering is low given the layer's depth.
Suspect terrain for human triggering includes steep, shallow, and rocky terrain where the snowpack transitions from thin to thick.
Friday saw wind slab and storm slab avalanches. The wind slab avalanches were triggered remotely and with ski cuts. Both were in the alpine, on northerly aspects and were 30 cm deep running on facets that were buried on April 1st. In the northern part of our region, there was a size 2 natural storm slab avalanche. This occurred in the alpine on an east-facing slope and also failed on a surface that was buried 30 cm down.
On Thursday, there were reports of several cornice-triggered avalanches throughout the Monashees up to size 3. These avalanches did not step down to deeper weak layers.
On Wednesday, storm snow continued to be reactive to natural and human triggers. A few surprise skier-triggered storm slab avalanches were reported up to size 2. Naturally triggered storm slab and wind slab avalanches were observed up to size 2.5. Many of these avalanches are reported to be failing on a surface hoar layer buried near the end of March or a crust on solar aspects. Avalanche activity has primarily been observed on north and east aspects from 1700 to 2200 m. Reports indicate that the Selkirks seem to be the most reactive with rider remote-triggered slabs in the upper 50 cm of snow.
By Sunday morning 15 to 20 cm of recent storm snow will be added to the 15 to 40 cm of settling snow. Southerly winds will be increasing and may start creating fresh wind slabs out of this top layer of snow in exposed terrain. A widespread crust is present 30 to 50 cm below the surface, except for on north-facing slopes at treeline and above. In these locations, instead of a crust, you may find faceted surfaces, and surface hoar in sheltered terrain. Further down in the snowpack, 60 cm down, a surface hoar layer has been reactive to human triggering. This has occurred primarily in the Selkirks, on northeasterly slopes from 1700 m to 2100 m.
The mid-snowpack is generally strong but the lower snowpack is a different story. The November facets are still prominent at the base of the snowpack. This layer remains a concern in rocky, shallow, or thin to thick snowpack areas at treeline and above.
Saturday Night
Mostly cloudy, around 5 cm accumulation, winds southwest 25 km/h, freezing levels 1500 m.
Sunday
Cloudy, 5 to 8 cm accumulation throughout the day, winds south 30 to 40 km/h, freezing levels potentially getting up to 2000 m.
Monday
A mix of sun and cloud, up to 10 cm accumulation by the morning with another 10 to 20 cm during the day, winds southwest 30 km/h switching to the northeast by the end of the day, freezing levels 1500 to 2000 m.
Tuesday
Mostly cloudy, up to 8 cm accumulation in some places, winds southwest 20 to 25 km/h, freezing levels to 1500 m.
More details can be found in the Mountain Weather Forecast.
