Avalanche Forecast
Issued: Jan 22nd, 2020 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs.
jfloyer,
Avalanche Canada
Only light amounts of new snow are expected, but strong winds are likely to set up fresh wind slabs in exposed areas.
Summary
Confidence
Moderate - Uncertainty is due to the extreme variability of wind effect on the snowpack.
Weather Forecast
Wednesday night: Around 5 cm new snow. Strong southwesterly winds. Freezing level around 600 m.
Thursday: 5-10 cm new snow. Moderate southwesterly winds. Freezing level rising to around 1200 m.
Friday: 5-10 cm new snow. Strong southwesterly winds. Freezing level around 1000 m.
Saturday: Around 5 cm new snow. Strong southwesterly winds. Freezing level around 1000 m.
Avalanche Summary
Wind slab avalanches, skier triggered size 1.5 and natural size 2.5 were observed in the Howson ranges Monday.
Over the weekend, a natural storm cycle was observed at treeline and below. Slabs were soft and thin but propagated widely resulting in avalanches up to size 2. They ran on the faceted interface buried January 17th.
There have been reports trickling in over the past month of natural persistent slab avalanches up to size 3 in the Bulkley Valley. These are thought to have been failing on the November crust/facet layer near the ground. The last reported activity at this interface was Monday January 13th.
Snowpack Summary
Southerly winds have formed fresh wind slabs from 10-20 cm (up to 50 cm in the Howson area) of recent snow in places that were previously scoured by northeasterly arctic outflows. In wind sheltered areas at treeline and below, the recent snow sits on a layer of touchy facets.
A layer of surface hoar now buried up to 1 m below the surface may also be found at treeline. A deep crust/facet layer lurks at the base of the snowpack. A couple of large avalanches are suspected to have run on this interface in the last few weeks. These larger avalanches have been specific to lee and cross-loaded features in the alpine.Total snow depths of 30-40 cm have been reported at alpine elevations in the Smithers area, with depths diminishing rapidly with elevation below 1500 metres. For most areas where snow cover exists, the snowpack is capped by a supportive melt-freeze crust. Above 1800 metres a light cover of windblown snow is reported to have formed thin wind slabs in lee areas.Â
Terrain and Travel
- Recent wind has varied in direction so watch for wind slabs on all aspects.
- Be careful with wind slabs, especially in steep, unsupported and/or convex terrain features.
- Small avalanches can have serious consequences in extreme terrain. Carefully evaluate your line for wind slab hazard before you commit to it.
Problems
Wind Slabs
Around 20 cm soft snow near the surface is available to form wind slabs on north through east aspect slopes in exposed areas. In sheltered areas, the recent snow sits over weak, sugary facets and will likely continue to be reactive to human triggering on this interface.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Jan 23rd, 2020 5:00PM
