More precipitation is forecasted for Saturday, with snow at high elevations and rain below. Be cautious of periods of rapid precipitation loading, as avalanche activity may increase.
Confidence
Moderate - Intensity of incoming weather systems is uncertain
Weather Forecast
SATURDAY: Cloudy with snow at higher elevations and rain below, accumulation 20 to 30 mm water equivalent, strong southerly winds, treeline temperature 3 C, freezing level 1600 m.SUNDAY: Mostly cloudy with early-morning precipitation, accumulation 10 to 20 mm water equivalent, light westerly winds, alpine temperature 1 C, freezing level 1400 m.MONDAY: Mostly cloudy, light southwesterly winds, alpine temperature 2 C, freezing level 1600 m.
Avalanche Summary
On Thursday, it was easy to initiate large wet loose avalanche in steep terrain below treeline. The avalanches were generally slow but ran far.
Snowpack Summary
Around 15 to 60 mm of rain fell on the snowpack up to around 1700 m on Thursday and Friday, with precipitation as snow above. More of the same is forecasted for Saturday. In alpine terrain, the snow will create new storm slabs. This snow overlies variable surfaces including crusts and facets, which are more likely to be problematic on shady aspects. The snowpack below this is generally strong.At treeline and below treeline elevations, a spring snowpack exists. Rain is saturating and weakening the upper snowpack, allowing for loose wet avalanches. This wet snow may freeze overnight at higher elevations with cool temperatures. The mid and lower snowpack are strong.
Problems
Storm Slabs
Storm Slab avalanches are the release of a cohesive layer (a slab) of new snow that breaks within new snow or on the old snow surface. Storm-slabs typically last between a few hours and few days (following snowfall). Storm-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.
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.