High winds overnight has likely added to the slab problem, causing the hazard rating in the alpine to be considerable. Up to 16mm of precipitation for Saturday will also bump up the alpine hazard then. Otherwise, spring conditions continue.
Weather Forecast
The South Columbia's will be dry due to a ridge of high pressure, while the North will be wetter as a low moves through. Rogers Pass is on the boundary, so cloud and a chance of convective precipitation is expected. More unsettled weather is forecasted for the weekend, starting on Friday with the bulk of the rain (up to 16 mm) arriving Saturday.
Snowpack Summary
Variable springtime conditions: a 10-15cm thick crust on solar aspects and lower elevations overlies near isothermal snowpack which firms up overnight, and looses strength during the warmth of the day. In the alpine, a mix of hard and soft slab persists, with dry snow on polar aspects. Lots of variability in snow depth across terrain.
Avalanche Summary
The number of avalanche observations has dropped off, in part due to fewer people in the backcountry to report. Cornice failures remain the biggest concern for triggering larger slab avalanches, which are mostly failing on the April 3 PWL (sun crust-surface hoar combo), down 40-80cm. Cloud today will reduce the likelihood of moist avalanches.
Confidence
Timing, track, or intensity of incoming weather system is uncertain on Saturday
Problems
Wind Slabs
Wind Slab avalanches are the release of a cohesive layer of snow (a slab) formed by the wind. Wind typically transports snow from the upwind sides of terrain features and deposits snow on the downwind side. Wind slabs are often smooth and rounded and sometimes sound hollow, and can range from soft to hard. Wind 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.
Persistent Slabs
Persistent Slab avalanches are the release of a cohesive layer of snow (a slab) in the middle to upper snowpack, when the bond to an underlying persistent weak layer breaks. Persistent layers include: surface hoar, depth hoar, near-surface facets, or faceted snow. Persistent weak layers can continue to produce avalanches for days, weeks or even months, making them especially dangerous and tricky. As additional snow and wind events build a thicker slab on top of the persistent weak layer, this avalanche problem may develop into a Deep Persistent Slab.
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.