The heat is on! If you're hoping to get one more alpine mission in, you need to get out super early Saturday and plan to be out of avalanche terrain no later than lunch time. Watch for the odd small wind slab in the alpine Saturday morning.
Weather Forecast
A significant pattern change is expected to commence Saturday as a strong ridge begins to build. After Friday night, temperatures are expected to remain well above freezing at all elevations for the foreseeable future. SATURDAY: Broken cloud cover, freezing level beginning around 1200 m, climbing to around 2500 m in the afternoon, no significant precipitation, light variable wind at and below treeline, moderate southwest wind at ridgetop. SUNDAY: Few clouds, freezing level beginning near 2700 m, rising to around 3500 m by the afternoon, no significant precipitation, moderate southwest wind. MONDAY: Mostly clear skies, freezing level near 3500 m all day, no significant precipitation, light south/southeast wind.
Avalanche Summary
No new avalanches reported. In the neighboring Sea-2-Sky region on Thursday, a size 1 storm slab was accidentally triggered by a skier on a north aspect at 2300 m. The slab ran on the crust that's just underneath the most recent storm snow.
Snowpack Summary
Cornices are large, fragile, and could trigger deep slab avalanches that run to valley bottoms. Monitoring the overnight freeze of the snow surface is very important during the spring. If the snow surface does not freeze overnight or if the crust is only a few cm thick, the effect of daytime heating and solar radiation 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 sun can weaken the snowpack. There is an old crust layer down approximately 50cm in the Duffey area and north of Pemberton. This layer has generally been dormant but did produce a couple large avalanches during the last major warming event. With continued warming, this layer could wake-up in isolated locations such as steep, rocky faces. Glide cracks are widespread, active, and best avoided. 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
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.
Cornices
Cornice Fall is the release of an overhanging mass of snow that forms as the wind moves snow over a sharp terrain feature, such as a ridge, and deposits snow on the downwind (leeward) side. Cornices range in size from small wind drifts of soft snow to large overhangs of hard snow that are 30 feet (10 meters) or taller. They can break off the terrain suddenly and pull back onto the ridge top and catch people by surprise even on the flat ground above the slope. Even small cornices can have enough mass to be destructive and deadly. Cornice Fall can entrain loose surface snow or trigger slab avalanches.
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.