Avalanche Forecast

High - We have a good understanding of the snowpack structure and confidence in the weather forecast

Another intense storm hits the region on Thursday then things begin to clear up by the weekend.

WEDNESDAY NIGHT: Frontal system crosses the region overnight delivering 10-20 cm of new snow, strong wind from the south, freezing level around 500 m with alpine temperatures around -5 C.

THURSDAY: Convective flurries continue throughout the day with another 10-20 cm (more near the coast), strong wind from the south, freezing level around 500 m with alpine temperatures around -5 C.

FRIDAY: Mostly cloudy with scattered flurries and another 5-15 cm of snow, light to moderate wind from the south, alpine high temperatures around -5 C.

SATURDAY: Sunny, light northeast wind, alpine high temperatures around -2 C.

A steady pulse of storms over the past week has produced numerous cycles of large natural avalanches. These avalanches have failed on a mix of storm interfaces and persistent weak layers. Similar activity can be expected on Thursday.

Natural storm slab avalanches (size 2-2.5) were reported at higher elevations on Tuesday, and several size 1-2 human triggered slabs were reported on north facing treeline slopes. The human triggered slabs failed on the March 1st surface hoar layer. On Monday several natural size 2 avalanches were observed on open rollovers at treeline, also failing on the March 1st surface hoar. On Friday and Saturday there were reports of natural and skier triggered size 2-3 avalanches failing on the February 19th surface hoar layer, primarily on north and east facing slopes around treeline.

There have also been some isolated reports of very large (size 2.5-2.5) natural and explosive triggered avalanches on deeper weak layers (including one that occurred on March 1 that failed on the January facet layer on a northeast slope at 1500 m near Kitimat and a few on March 2 that failed on basal facets on east and southeast alpine slopes near Ningunsaw).

Large cornice and glide crack failures continue to be reported too.  

Fresh slabs will form as another storm delivers 20-40 cm of snow by Thursday afternoon accompanied with strong south wind.

Recent storms have buried two layers of surface hoar that continue to be reactive and produce large avalanches. One layer was buried on March 1st and is currently 30-60 cm below the surface, the other was buried on February 19th and is currently 75-125 cm below the surface. On solar aspects (south through west) surface hoar may be resting on a buried crust which could be a very problematic setup. A rain crust exists below 1000 m. Be very suspect of slopes at treeline elevations and at the higher end of below treeline where preserved surface hoar most likely exists.

A layer of weak and sugary faceted grains that formed in January may be found about 120 to 170 cm deep, and an early-season melt-freeze crust linger at the base of the snowpack. These layers have produced a few very large natural and explosive triggered avalanches over the past two weeks.

• Avoid all avalanche terrain during periods of heavy loading from new snow and wind.
• Only the most simple non-avalanche terrain free of overhead hazard is appropriate at this time.
• Storm slabs in motion may step down to deeper layers resulting in large avalanches.