Northwest Coastal

Heavy snowfall and ongoing strong winds are expected to keep the hazard at HIGH on Monday in the deepest snowfall areas.  Stick to super mellow terrain and avoid exposure to avalanche terrain during the storm.

Low - Due to the number of field observations

The stormy conditions continue with another 10-25cm of snowfall forecast Sunday overnight and early Monday. Amounts will be greatest along the coast and taper substantially as you move inland. Alpine winds should be moderate to strong from the south and freezing levels are expected to be 1000-1200m. A bit of a break is expected for Monday afternoon before another storm pulse arrives Monday overnight or Tuesday morning. 10-15cm of snowfall is expected for Tuesday with freezing levels around 700m and moderate to strong southerly alpine winds. Unsettled conditions are expected for Wednesday with light flurries.

On Saturday, numerous explosive-triggered wind slabs size 1-2 were reported north of Stewart.  These were primarily on west through north aspects around 1400m and thicknesses ranged from 10cm to 60cm.  Two of these explosive-triggered avalanches caused sympathetic avalanches to release 70-90m away.  A skier accidental avalanche size 1.5 was also reported near Terrace.  This was a 30cm thick storm slab on a north aspect at 1400m.  Some isolated natural avalanches were also reported from 450m elevation but it is expected that localized large surface hoar near a lake is the culprit.  On Friday, three human-triggered avalanches were reported north of Terrace. A ski-cut produced a size 1.5 on a north aspect at 1300m, a skier accidently triggered a size 1 on a NW aspect at 1400m, and a skier remotely triggered a size 1 from 5m away on a NE aspect at 900m. All three were described as storm slabs 25-30cm thick failing on a layer of surface hoar from January 9th. Also reported on Friday were isolated natural avalanches up to size 2 in the alpine and treeline, as well as loose moist avalanches from steep rocky features below treeline.

Around 15cm of new storm snow has now buried a layer of surface hoar from mid-January. Down 30-60cm is the early-January surface hoar layer which seems to still be the layer of most concern. This layer is reported to be a concern for remote triggering which means the propagation potential is relatively high. Two other weak layers from December are in the upper meter of the snowpack.  These layers are generally considered dormant but are still reacting to snowpack tests and have the potential to wake-up to heavy loading, rapid warming, or avalanches stepping-down. Recent strong to extreme southeast winds have loaded leeward features on west through north aspect slopes.