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 and southeast 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, north of Stewart, explosives avalanche control produced several small (size 1.5), widely propagating avalanches on steep cutbanks.
Looking forward to Saturday, natural and human triggered avalanches will be likely in areas that are seeing rapid loading from new snow and wind.
By Saturday afternoon, 25 to 50 cm of recent storm snow may have fallen with southerly wind forming deeper deposits on northerly aspects. 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.
Friday Night
Cloudy with 5 to 10 cm of snow, 15 to 20 cm around Stewart. 30 to 40 km/h southeast ridgetop wind. Treeline temperature -3 °C.
Saturday
Cloudy with 2 to 5 cm of snow, 10 to 20 cm around Stewart. 30 to 50 km/h south ridgetop wind. Treeline temperature -2 °C.
Sunday
Cloudy with 7-10 cm of snow, up to 20 cm around Stewart. 25 to 35 km/h south or southeast ridgetop wind. Freezing level rising to 1200 m.
Monday
Mostly cloudy with 2-5 cm of snow. 10 to 20 km/h south ridgetop wind. Freezing level falling to valley bottom overnight and rising back to 750 m through the day.
More details can be found in the Mountain Weather Forecast.
