We're entering a bit of a stormy period for the next few days. The precipitation amounts are pretty modest, but the series of weak disturbances may build shallow storm slabs in high elevation terrain.
Confidence
Moderate - Forecast snowfall amounts are uncertain on Tuesday
Weather Forecast
We're entering a bit of a stormy period for the next few days. The precipitation amounts are pretty modest, but the series of weak disturbances could offer a nice refresh at upper elevations.MONDAY NIGHT: Freezing level around 2000 m, light variable wind, 1 to 5 cm of snow possible at upper elevations.TUESDAY: Overcast, freezing level around 1800 m, light southerly wind, 5 to 10 cm of snow possible at upper elevations, an additional 4 to 8 cm of snow possible Tuesday night.WEDNESDAY: Broken cloud cover, freezing level around 2000 m, light southerly wind, 1 to 5 cm of snow possible at upper elevations.THURSDAY: Scattered cloud cover, freezing level around 1800 m, light to moderate southwest wind, trace of snow possible at upper elevations.
Avalanche Summary
On Monday there was a natural loose wet avalanche cycle to size 1.5 on solar aspects as the new snow ran on the crust. On Sunday storm slabs to size 1.5 were susceptible to explosive control work to size 1.5 on north and northeast facing terrain between 1900 and 2000 m. Numerous loose avalanches to size 1.5 were reported from terrain that generally faces north around 2000 m on Saturday. A natural cornice failure also produced a size 2 slab on a northeast facing slope at 2200 m on Saturday.
Snowpack Summary
Sunday night the region picked up 10 cm of moist snow. This snow rests on a supportive crust above about 1400 m. Below 1400 m the snowpack is becoming isothermal. During the heat of the day, especially under direct sun, the snow surface becomes moist or wet almost everywhere. The exception being high elevation north facing features. With spring conditions, the avalanche hazard will fluctuate greatly depending on the strength of the overnight re-freeze and how quickly the snowpack is warmed up.Steep, north facing, alpine terrain may still hold a cold, dry, snowpack where a well settled slab rests on weak facets (sugary snow). Although unlikely, human triggering of persistent slabs on this layer may still be possible, especially in rocky alpine terrain with a shallow or highly variable depth snowpack.
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.
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.