Avalanche Forecast

Moderate - Intensity of incoming weather systems is uncertain

TUESDAY NIGHT: Flurries, accumulation trace around the Duffy and up to 10 cm around the Coquihalla , moderate west gusting to strong, freezing level valley bottomWEDNESDAY: Snow, accumulation 15-25 cm, moderate increasing strong southwest wind, freezing level below 1000 mTHURSDAY: Snow, accumulation 15-30 cm, moderate to strong southwest ridge wind, freezing level 1400 m around the Duffy and rising to 1800m around the CoquihallaFRIDAY: Snow, accumulation 25-35 cm, strong southwest ridge wind with extreme gusts, freezing level around 1500m

On Monday, shooting cracks and other signs of instability were reported in the Duffy area. In the neighboring Sea to Sky region, the new storm snow has already produced small (size 1) storm slabs avalanches reacting to skier traffic. Similar avalanche activity can be expected in the South Coast Inland as the storm progresses.Over a week ago (Saturday, Dec 1), two very large (size 3) avalanches were observed in the Joffre Lakes area. These avalanches were on high alpine features and ‘stepped down’ to previous summer snow cover. It is possible that a weak interface exists near the bottom of the snowpack in specific alpine terrain.

Snowfall starting Sunday night has deposited 20-30 cm at higher elevations in the region. This has buried a weak, variable surface layer covering 20-30 cm of low density faceted snow. The new snow is initially not bonding well with the older snow. Prior to this storm, alpine snowpack depths varied around 120-180 cm, with an early November crust at bottom of the snowpack (down 100-120cm). This crust appears to be breaking down at higher elevations and has been unreactive to snowpack tests. Snowpack depths disappear quickly with decreasing elevations and new snow may just cover early season hazards at lower elevations.