Regions
Northwest Inland.
Avoid steep, rocky terrain in the alpine where there is a shallow or highly variable snowpack depth. This will reduce the likelihood of triggering large persistent slab avalanches.
Weather Forecast
THURSDAY NIGHT: Increasing cloudiness / Light to moderate, southwesterly winds / Alpine low 5 C / Freezing level 2400 m.FRIDAY: Mostly cloudy / Moderate, southeasterly winds / Alpine high 5 C / Freezing level 2400 m.SATURDAY: Snow/rain; 5-10 mm precipitation / Moderate, southwesterly winds / Alpine high -1 C / Freezing level 1500 m.SUNDAY: Mix of sun and cloud / Light, easterly winds / Alpine high -1 C / Freezing level 1600 m.
Avalanche Summary
The natural avalanche activity has been slowing down a bit. However, as of Wednesday afternoon, naturally triggered loose wet avalanches up to 2.5 on sun-exposed aspects continue to be reported.Reports from Monday included an observation of a size 3 (very large) persistent slab running full path and within 100 metres of the viewing platform at Twin Falls. This highlights the current elevated danger in lower elevation areas threatened by large overhead avalanche paths. Please see the Northwest Coastal forecast's avalanche summary for a description of the natural avalanche cycle that is ongoing in this neighboring region. With limited observations inland, it is advised to treat this activity as an indication of potential similarities to this region.Looking forward, expect heightened avalanche activity to continue and potentially expand to all aspects, so long as temperatures remain elevated and overnight freezing of the snow surface remains weak.
Snowpack Summary
Up to 50 cm of settled snow from storms last week sits on the surface. With the help of warm temperatures, the 50 cm of snow from last week's storm has either settled into a slab on shaded aspects or becomes increasingly isothermal (slushy) on sun-exposed aspects. Where it exists as a slab, it overlies weak facets (sugary snow). The prolonged period of cold temperatures in February had an overall effect of weakening the upper and mid-snowpack, as well as the basal (lower) snowpack in shallow areas. These weaknesses are increasingly being tested under the pattern of strong warming currently affecting the region.
Problems
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.