Regions
Northwest Inland.
Observations and data are limited. Be sure to read the Northwest Coast bulletin for information on a touchy persistent slab problem, which may also be present and active in some inland areas.
Confidence
Poor - Due to the number of field observations
Weather Forecast
Thursday: Increasing cloud with light snow developing late. The freezing level is around 1500 m. Winds increase to strong or extreme from the S-SW. Friday: Light snow. The freezing level is near 1200 m and winds are strong from the south. Saturday: Cloudy with flurries. The freezing level is around 1000 m and winds are moderate from the SW.
Avalanche Summary
On Tuesday, several loose wet avalanches to size 2 were reported from steep sun-exposed slopes. Some of these did trigger slabs up to size 2.5, potentially releasing on the March 25th surface hoar layer. Observers near the Ningunsaw Pass (northern part of the region) have been reported significant activity on the March 25th interface. For the past few days there have been reports of natural, skier-triggered, and remotely triggered avalanches up to size 3.
Snowpack Summary
You may still find dry powder on higher north aspects, but any sun exposed slope will likely be in a melt-freeze cycle. Recent winds have scoured windward slopes and loaded lee features. A crust with surface hoar buried on March 25th, down around 50 cm, has been identified as a potential problem in parts of the forecast region, but its sensitively and distribution are largely unknown. At the base of the snowpack, especially in areas of shallow snow, weak facets may be found. Cornices are now large and potentially fragile, and solar aspects are becoming active in the late afternoons.
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.
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.