Confidence
Fair - Intensity of incoming weather is uncertain
Weather Forecast
Thursday: should stay cold and dry, although some areas may experience inversion conditions with warmer temps higher up. Winds will increase slightly but should stay in the moderate range, and will shift back around to the west. Friday: a storm is approaching, which will gradually increase in intensity through the day. Anticipated amounts are around 5-10 cm new snow with temperatures around -10C. Winds will shift round to the SW. Friday night will see higher snowfall amounts, in the region of 15-20 cm. On Saturday, a further 5-10 cm new snow is anticipated, with freezing levels rising to around 1000 m.
Avalanche Summary
Many natural loose snow avalanches were noted on Tuesday in the Coquihalla. Small soft slabs could be skier-triggered on Wednesday.
Snowpack Summary
30-80 cm very low density snow has accumulated over the last few days. The Coquihalla and areas around Hope have seen the highest amounts. Winds recently picked up into moderate range from the southwest - just enough to create some soft slabs on lee slopes in exposed areas. Below the storm snow lies a rain crust at lower elevations (up to around 1800 m) and old wind slabs in exposed areas at higher elevations. Weak layers lower in the snowpack have generally ceased to be of concern, except perhaps in thin rocky areas.
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 Dry
Loose Dry avalanches are the release of dry unconsolidated snow and typically occur within layers of soft snow near the surface of the snowpack. These avalanches start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. Other names for loose-dry avalanches include point-release avalanches or sluffs.