Spring Conditions. Cloudy and cooler conditions will reduce the size and likelihood of loose wet and wet slab avalanches. New surface crusts are expected to develop over the next few days.
Weather Forecast
Cloud developing inland overnight with light southeast winds and freezing levels near 3000 metres..Light to moderate convective rain showers on Friday with gusty winds and freezing levels close to 3000 metres. Moderate rain on Saturday with light winds and freezing levels dropping to 2500 metres. Cooling trend continuing on Sunday with freezing levels down to 2000 metres by the end of the day.
Avalanche Summary
No new avalanches reported. On Tuesday a size 3.0 wet slab avalanches was explosives triggered in the Duffey Lake area, this large avalanche released down to the ground on a northwest aspect at 2200 metres and ran to the valley bottom. Most commercial operations in the region have finished their season and data is sparse.
Snowpack Summary
Forecast cloud, cooling, and new snow at higher elevations will reduce the likelihood of loose wet and wet slab avalanches. Areas that get rain on top of a snowpack that has not re-frozen may continue to see sporadic wet slab avalanches. Monitoring the overnight freeze of the snow surface is very important. If the snow surface does not freeze overnight or if the crust is only a few cm thick, the effect of daytime heating or rain will weaken the snowpack much more quickly than it would if there is a well frozen thick crust. This is because the crust must first melt before the heat can weaken the snowpack. Low elevation and thin snowpack areas have become isothermal, meaning the snowpack is 0 degrees Celsius throughout. An isothermal snowpack is more prone to full depth wet slab avalanches during the heat of the day, especially on steep rocky faces.
Problems
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.