The big storm may have passed, but elevated danger ratings will persist, especially with forecast warm temperatures. If the sun comes out, the avalanche danger may become HIGH.
Confidence
Fair - Timing or intensity of solar radiation is uncertain
Weather Forecast
We can expect a mix of sun and cloud for the forecast period as a ridge of high pressure pushes into the province. Ridgetop winds should remain light to moderate from the west-northwest. Freezing levels should sit at about 1500m on Tuesday, rising to about 1800m on Wednesday and then dropping back to about 1500m on Thursday.
Avalanche Summary
On Saturday an avalanche resulted in a fatality in the southwest corner of the region. More details will follow as they become available. On Sunday a widespread natural avalanche cycle to size 3.5 took place. The avalanche activity occurred in response to strong wind, snow and warming over the weekend. Much of the activity occurred within the storm snow, while many avalanches stepped down to the February 10th interface. On Monday, explosives control triggered a few persistent slab avalanches to size 3.5. On the same day, a group of slackcountry skiers triggered a size 2.5 slab avalanche. Nobody was injured in the event.Looking forward, another natural cycle may occur on solar aspects with forecast sunny breaks and warming.
Snowpack Summary
In some areas over 80cm of recent storm snow overlies small surface hoar in sheltered areas and a sun crust on previously sun exposed slopes. In wind exposed terrain these new accumulations have been pushed into much deeper deposits by generally moderate southwest winds. Wind and warming have also created an "upside down" storm slab which may be particularly touchy where it overlies the buried crust. Many slopes below 1850m saw rain over the weekend and the snowpack at lower elevations is now mostly saturated. At ridgetop cornices are large, unsupported and waiting for the right trigger.We're still seeing avalanches on a mix of weak surfaces which were buried on February 10th. This persistent interface lies between 100 and 200cm below the surface, and includes surface hoar, well developed facets and a mix of hard surfaces which remain widespread at all aspects and elevations. This deeply buried layer still has the potential to "wake up" and create very large and destructive avalanches. Possible triggers include a surface avalanche in motion or a cornice fall.For the most part, the mid and lower snowpack are strong and well consolidated.
Problems
Storm Slabs
Storm Slab avalanches are the release of a cohesive layer (a slab) of new snow that breaks within new snow or on the old snow surface. Storm-slabs typically last between a few hours and few days (following snowfall). Storm-slabs that form over a persistent weak layer (surface hoar, depth hoar, or near-surface facets) may be termed Persistent Slabs or may develop into Persistent Slabs.
Persistent Slabs
Persistent Slab avalanches are the release of a cohesive layer of snow (a slab) in the middle to upper snowpack, when the bond to an underlying persistent weak layer breaks. Persistent layers include: surface hoar, depth hoar, near-surface facets, or faceted snow. Persistent weak layers can continue to produce avalanches for days, weeks or even months, making them especially dangerous and tricky. As additional snow and wind events build a thicker slab on top of the persistent weak layer, this avalanche problem may develop into a Deep Persistent Slab.
Loose Wet
Loose Wet avalanches are the release of wet unconsolidated snow or slush. These avalanches typically occur within layers of wet snow near the surface of the snowpack, but they may quickly gouge into lower snowpack layers. Like Loose Dry Avalanches, they start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. Other names for loose-wet avalanches include point-release avalanches or sluffs. Loose Wet avalanches can trigger slab avalanches that break into deeper snow layers.