This is last of our regularly scheduled avalanche bulletins. We will update this as needed during the next few weeks. Refer to our weather stations for current temperatures and precipitation amounts to help plan your trips. Enjoy the spring skiing!
Weather Forecast
The forecast for April 30th and into the first few days of May is for cloudy days with snow flurries at higher elevations and rain showers at lower elevations. Temperatures will be cooler during the day but over night freezes may be fairly minimal due to the cloud cover, except at high elevations. Freezing levels between 2000-2400 m are expected.
Snowpack Summary
5-10cm of new snow in the alpine on April 29th. Crust or moist snow on all solar aspects depending on temperatures. Buried temperature crusts to 2600m on all aspects and to ridge top on solar slopes. Moist snow at lower elevations, with the entire snowpack becoming isothermal near valley bottom.
Avalanche Summary
We have seen regular loose wet and wet slab avalanches up to size 3 running on all aspects in the afternoon and early evening during the warmest times of the day. Cornice failures have also been fairly regular, occasionally triggering slabs on the slopes below.
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.
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.
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.