Choose mellow, low consequence terrain during the storm. The heaviest snowfall is expected around Stewart.
If your area gets less than 30 cm of snow, lower the danger one level.
Expect fresh, reactive storm slabs to be forming as new snow falls with strong south winds. In lower snow areas, there may only be a problem on wind-loaded slopes.
This new snow may be sitting on weak surface hoar or facets.
A weak layer buried 100 to 300 cm remains a concern.
Avoid shallow rocky areas where the snow transitions from thick to thin and triggering this layer is more likely.
If triggered the resulting avalanche would be very large and destructive.
On Friday, several size 1 to 2 natural storm slab avalanches were reported. These avalanches entrained moist snow at lower elevations, acting like loose wet avalanches. North of Stewart, avalanche control with explosives produced several small (size 1.5) widely propagating avalanches on steep cutbanks.
Looking forward, natural and human-triggered avalanches will remain likely in areas that are seeing rapid loading from new snow and wind.
By Sunday afternoon, 25 to 50 cm of recent storm snow may have fallen with southerly wind forming deeper deposits on north-facing slopes. This recent snow will overlie a variety of surfaces including a layer of surface hoar in sheltered terrain and wind-affected snow or a crust in exposed terrain.
In sheltered terrain, a thick layer (40 to 70) cm of faceted snow overlies a crust and layer of surface hoar from late January.
Deeper in the snowpack, another layer of surface hoar was buried near the middle of January.
A weak layer of facets and a crust from early December varies in depth from 100 to 300 cm. This layer remains a concern in this region.
Saturday Night
Cloudy with 10 to 20 cm of snow. 50 to 70 km/h southwest ridgetop wind. Treeline temperature -3 °C.
Sunday
Cloudy with up to 15 cm of snow. 30 to 50 km/h southwest ridgetop wind. Treeline temperature -3 °C.
Monday
Partly cloudy. 10 to 20 km/h southwest ridgetop wind. Treeline temperature -5 °C.
Tuesday
Mostly cloudy with trace snow. 30 to 50 km/h southwest ridgetop wind. Treeline temperature -3 °C.
More details can be found in the Mountain Weather Forecast.
