Regions
Northwest Coastal.
Spring Conditions. The storm is over, however wind slabs left behind may be easy to trigger at higher elevations. Watch for a rapid change to sunny and hot conditions. Areas with new snow may release naturally when the sun comes out.
Weather Forecast
Clearing overnight with light northeast winds replacing the strong southwest winds during the storm. Freezing levels down to 500 metres overnight and then rising up to 2500 metres on Tuesday under clear skies and strong solar radiation. Clear and sunny on Wednesday with freezing level at 2500 metres. Clear and sunny on Thursday, some chance that the ridge of high pressure will break down during the day resulting in high cloud.
Avalanche Summary
Wet slab avalanches releasing down to the ground have been reported along the highway corridor near Stewart from mid-elevation paths. Wind slabs and cornice falls are suspected in the high alpine, but visibility has been poor and we have no new reports from alpine elevations.
Snowpack Summary
There has been 20-40 mm of precipitation in the past few days. Most of this has fallen as rain up to at least 1500 metres. Most of the precipitation has been in the near coastal ranges, with Stewart and Kitimat receiving closer to 40mm and areas around Terrace closer to 20mm. Winds have been strong out of the south; reports from Stewart of gusts above 100 km/hr on Monday that have developed wind slabs in the high alpine. Rain has soaked the snowpack at lower elevations. Some recent crusts within the upper snowpack may continue to provide a sliding layer for loose wet avalanches when forecast temperatures and freezing levels spike in the next few days.
Problems
Wind Slabs
Wind Slab avalanches are the release of a cohesive layer of snow (a slab) formed by the wind. Wind typically transports snow from the upwind sides of terrain features and deposits snow on the downwind side. Wind slabs are often smooth and rounded and sometimes sound hollow, and can range from soft to hard. Wind 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.
Wet Slabs
Wet Slab avalanches are the release of a cohesive layer of snow (a slab) that is generally moist or wet when the flow of liquid water weakens the bond between the slab and the surface below (snow or ground). They often occur during prolonged warming events and/or rain-on-snow events. Wet Slabs can be very unpredictable and destructive.
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.