Avalanche Forecast

High - The weather pattern is stable

Thursday: Mainly cloudy with isolated flurries and a trace of new snow. Winds light from the southwest. Alpine temperatures of -7.Friday: Cloudy with scattered flurries and up to 5cm of new snow. Winds moderate from the southwest. Alpine temperatures of -8.Saturday: Mainly cloudy with isolated flurries and a trace of new snow. Winds light to moderate from the southeast. Freezing levels rising to 800 metres with alpine temperatures around -4.

Reports from yesterday included a MIN report of an avalanche involvement in the adjacent South Coast Inland region, notable for illustrating the heightened consequences of triggering hard wind slab from below the fracture line. No new natural avalanches have been observed, but slope cutting continues to produce Size 1 results in isolated pockets of wind slab. Reports from earlier in the week included two natural Size 1.5 wind slab avalanches with 40cm deep crowns occurring southwest of Whistler on Monday on steep southwest and southeast slopes. Explosives testing in the Whistler area on Monday successfully targeted several reverse loaded pockets of wind slab in the alpine to Size 1.

70-100 cm of storm snow accumulated in the region during a series of storms last week. The critical part of snowpack analysis under our current conditions is determining how the wind is redistributing this storm snow into wind slabs. Recent extreme northerly winds have "reverse loaded" much of the new snow onto southerly slopes that were previously scoured. Moderate northerly winds continued to promote this wind slab formation into Wednesday. The existence of wind slabs on solar aspects is important to note as clear skies will allow for strong solar radiation to affect these aspects. Up to 100 cm below the surface lies the Boxing Day interface, which consists of wind affected surfaces, faceted (sugary) snow, or surface hoar. Recent observations suggest the overlying snow is generally well bonded to this interface. The mid-December interface is now down 100-150 cm and is generally considered to be stable in this region. Snowpack layers below this are well bonded.