Regions
Northwest Inland.
Storm snow from the weekend has been redistributed into pockets of wind slab in the alpine. These may be reactive to human triggers, especially where they sit above a weak layer of surface hoar.
Confidence
Moderate - Timing, track, or intensity of incoming weather system is uncertain on Thursday
Weather Forecast
TUESDAY NIGHT - Cloudy with flurries, 2-4 cm / southwest winds, 20-40 km/h / alpine low temperature near -4WEDNESDAY - Cloudy with flurries, 2-4 cm / southwest winds 30-60 km/h / alpine high temperature near -2THURSDAY - Flurries, 10-15 cm / southwest winds 15-20 km/h / alpine high temperature near -2 FRIDAY - Flurries, 5-10 cm / southwest winds, 20-50 km/h / alpine high temperature near -2
Avalanche Summary
No new avalanches were reported in the region on Monday.A widespread natural avalanche cycle to size 3 was reported north of Hazelton on Sunday. Another notable report from the same area was of a remotely triggered (triggered from a distance) size 2.5 avalanche on a southwest aspect at 1650 m on Sunday. The report suggests that this avalanche may have triggered two more size 2 avalanches nearby.
Snowpack Summary
Up to 30 cm of snow has been blown into wind slabs at upper elevations. Due to previous variable wind directions, wind slabs may be found on all aspects in some areas.In the alpine and at upper treeline elevations, this recent snow likely sits on a weak layer of surface hoar (feathery crystals) in wind sheltered areas. At lower elevations, the recent precipitation fell as rain. The surface has formed a melt-freeze crust at treeline and below, and into some alpine areas as well.Generally speaking, areas north of Hazelton, and areas on the western edge of the region received the highest snowfall amounts in the last storm, while the south and east of the region received less. The northern areas have had more avalanche activity as a result of this, as noted in the Avalanche Summary. The bottom 30 to 50 cm of the snowpack consists of a weak combination of facets (sugary snow) and crusts, particularly in areas where the snowpack is shallow. It may be possible for large triggers such as cornice failures or rock fall to trigger avalanches on this layer.
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.