Regions
Northwest Inland.
New snow and strong wind will form fresh wind slabs in leeward areas at treeline and above. Wet or moist snow is still a concern for sunny or low elevation slopes, especially in the afternoon.
Confidence
Moderate - Timing, track, or intensity of incoming weather system is uncertain
Weather Forecast
TONIGHT: Mostly cloudy, light flurries. Accumulation 5-10 cm. Ridge wind strong to extreme, south. Alpine temperature near -4. Freezing level lowering to 600 m.WEDNESDAY: Mix of sun and cloud. Ridge wind strong to extreme, southeast. Alpine temperature near -4. Freezing level 1500 m. Snow beginning in the evening.THURSDAY: Flurries ending, mix of sun and cloud. Accumulation 10-15 cm. Ridge wind light to moderate, southwest. Alpine temperature near -5. Freezing level 1100 m.FRIDAY: Mix of sun and cloud, light flurries. Accumulation 2-5 cm. Ridge wind light to moderate, south. Alpine temperature near -5. Freezing level 1100 m.
Avalanche Summary
On Monday widespread loose, wet avalanche activity up to size 2 was reported on all aspects up to 1500 m in the Howson range.On Sunday there was also a report from the Howson range of a natural, size 2 wind slab release on a wind-loaded, northeast aspect at 2050 m, as well as evidence of previous widespread smaller activity as a result of wind loading.Last week, on Thursday a widespread natural avalanche cycle (up to size 2), triggered by intense wind loading was reported from the northern part of region.
Snowpack Summary
Rising freezing levels and daytime warming have created moist or wet snow surfaces on all but alpine, northerly aspects where 20 cm up to 50 cm of recent storm snow has been redistributed by strong winds. Weak layers buried around March 19th are roughly 40 cm below the surface (up to 100 cm in deeper snowpack areas). These weak layers include surface hoar on shaded aspects at high elevations and hard crust layers on solar aspects and below treeline.Near the bottom of the snowpack, weak and sugary facets are found in shallow, rocky snowpack areas. Storm slabs have stepped down to these facets and producing very large avalanches in northern parts of the region.
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.
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.