Reactive new wind slabs are expected to be the primary concern for Friday. However, if the sun makes an appearance during the afternoon, solar-triggered loose avalanches are also possible.
Recent southwest wind has formed wind slabs in exposed terrain at higher elevations. These slabs are expected to remain reactive to human triggering on Friday.
Solar-triggered loose avalanches are possible during the afternoon if the sun is shining brightly.
Unsettled conditions are expected for Friday before a weak storm system arrives early Saturday morning bringing light snowfall through most of Saturday.
Thursday night: Mainly cloudy with flurries, light to moderate SW wind, freezing level around 1000 m.
Friday: Mainly cloudy with a chance of both flurries and sunny breaks, light to moderate SW wind, freezing level reaching around 1400 m.
Saturday: Snowfall 5-15 cm, moderate S-SW wind, freezing level around 1300 m.
Sunday: A mix of sun and cloud, light W wind, freezing level around 1200 m.
On Wednesday, several natural storm slabs up to size 1.5 were observed in the Coquihalla area which occurred in the prior 24 hours. A small natural glide slab was also reported. In the north of the region, numerous natural size 1-1.5 wind slabs were reported on north and east aspects in the alpine.
On Tuesday, a natural size 2 storm slab was reported in the Coquihalla area as well as a natural size 1.5 wind slab on northeast aspect at 1900 m. In the north of the region, several human-triggered storm/wind slabs were reported up to size 2. These were on a variety of aspects between 1850 and 2400 m elevation. Slab thickness varied from 20-60 cm and a few were reported to be sliding on the underlying crust which was buried around March 12.
Prior to Thursday's snowfall, 20-40 cm of older storm snow which started accumulating on the weekend overlies a melt-freeze crust on sun-exposed aspects and wind-affected or well-settled old snow on shaded aspects. Recent observations suggest this snow is relatively well bonded to the underlying surface. Recent and ongoing wind has redistributed the storm snow into reactive wind slabs in exposed terrain.
In the north of the region, a crust/facet interface from February sits 30-60 cm deep and had been most problematic on north to northeast aspects around 1900-2100 m. This layer produced a number of avalanche in early March but is now considered dormant and no longer seems to be creating a problem in the region.
