Winter weather continues to bring snow to alpine elevations and rain below treeline. Expect avalanche danger to increase during the warmest part of the day.
Confidence
Moderate - Due to the number of field observations
Weather Forecast
Overnight: A couple of cm of new snow with moderate to strong southwest winds and freezing down to 1500 metres. Tuesday: Convective flurries during the day and then 3-5 cm of snow in the evening combined with moderate west winds and daytime freezing up to 2100 metres. Wednesday: Mostly sunny with moderate southwest winds and daytime freezing up to 2100 metres. Thursday: Mostly cloudy with periods of broken skies, light winds, and daytime freezing up to 2400 metres.
Avalanche Summary
Recent reports indicate several natural storm slab and cornice triggered avalanches to size 2 on all aspects tree line and above. Exposure to large overhanging cornices remains a significant concern.
Snowpack Summary
Moist new snow falling last week above tree line has been redistributed by south and southeast winds. Cornices remain large and continue to become more overhanging. The middle of the snowpack is generally well settled and continues to transition into a spring melt/freeze regime. Expect the entire thickness of the snowpack to be moist or wet at lower elevations. At upper elevations, the bottom third of the snowpack is composed of weak facets, however there still is uncertainty to this layer's reactivity. That being said, a heavy load like a cornice fall or rapid warming of the snowpack could potentially trigger this layer.
Problems
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.
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.