Wind and storm snow have formed reactive slabs particularly on leeward and open slopes at upper elevations. Deeper weak layers also remain a concern on isolated features at lower elevations.
Summary
Confidence
Moderate - Due to the number of field observations
Weather Forecast
TONIGHT: Flurries. Accumulation up to 5 cm. Ridge wind moderate, southeast. Temperature -9. Freezing level valley bottom.WEDNESDAY: Flurries. Accumulation 2-7 cm. Ridge wind light, south. Temperature -6. Freezing level 300 m.THURSDAY: Mainly cloudy, light flurries. Accumulation trace. Ridge wind light, east. Temperature -8. Freezing level valley bottom. FRIDAY: Mostly cloudy, light flurries. Accumulation up to 2 cm. Ridge wind light, south. Temperature -9. Freezing level valley bottom.
Avalanche Summary
On Monday there were reports from areas north of Kispiox of reactive storm slabs up to size 1.5 and 25 cm deep releasing with skier traffic on steeper, convex terrain.Reports from Saturday included one remotely (from a distance) triggered Size 1.5 wind slab releasing from a steeper northwest-facing slope at around 1500 m. The slab depth was 40-60 cm.Friday's reports showed a notable increase in persistent slab activity at lower elevations in the Howson Range. In this area, three Size 2 releases failed on steeper terrain with remote triggers on the mid-December weak layer, found 50 cm below the surface. Another report from last week mentioned numerous natural storm slab releases from Size 1-2 north of Kispiox. These were suspected to have released over a layer of surface hoar that may not be widely distributed.
Snowpack Summary
Recent light snowfalls have gradually brought about 20-40 cm of new snow to the region. This new snow has buried the mid-January interface which features a crust that exists well into the alpine and isolated pockets of surface hoar at lower alpine and treeline elevations. While its distribution is uncertain, this surface hoar remains an ongoing concern as the overlying storm snow settles into a slab above it.Below the mid-January interface, deeper weak layers in the snowpack include crusts and surface hoar layers that were buried in early-January and mid-December. Most recent reports suggest the old snow is well bonded to these layers, but recent persistent slab activity over a surface hoar and facet 'combo' at low elevations suggests that a dangerous persistent slab problem may be developing as the mid and upper snowpack consolidate into a stiffer slab over this layer.
jmcbride,
Avalanche Canada
