Regions
Northwest Inland.
Conditions vary throughout the region and observations are limited. If you're heading to deep snowpack areas in the region, differ to the NW Coast bulletin.
Confidence
Low - Due to the number of field observations
Weather Forecast
Sunday: Cloudy with a chance of flurries and sunny breaks late in the day. The freezing level is near valley bottom. Winds are generally light. Monday: A mix of sun and cloud. The freezing level is near valley bottom and ridge winds are light or moderate from the NW. Tuesday: A mix of sun and cloud. The freezing level is at valley bottom and ridge winds are light or moderate from the NW.
Avalanche Summary
There have been very few recent observations, although one report indicated numerous avalanches to size 3 occurred in low elevation terrain in the far west of the region. These avalanches likely occurred on Tuesday or Wednesday and failed in response to rain and warming below treeline. With forecast cooling, this type of activity should taper-off. Expect recently formed wind slabs to be sensitive to human triggering at higher elevations.
Snowpack Summary
Generally light amounts of new snow fell in the mountains around Smithers this week, while closer to 50 cm fell in areas further west. Strong winds may have redistributed much of this new snow into reactive wind slabs at higher elevations. Lower elevations likely have a dusting of new snow on a hard rain crust. There is a notable persistent weakness of buried surface hoar in many places, generally found between 25 and 60 cm deep. Wind and milder temperatures may have helped to promote slab development in the snow overlying this interface. Stay tuned to signs of instability like recent avalanches, whumpfing (reported in a few areas), and shooting cracks. The mid pack was reported to be well settled, although various levels of faceting can be certainly be expected in the lower snowpack.
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.