Regions
Vancouver Island.
Few reports of natural triggered avalanches up to size two were sent in to the bulletin. Thankfully there have not been any reports of human triggered avalanches, so it seems folks played safely out there.
Thanks to Russell Jensen for the report and pictures of the natural slide he came across in the Beaufort range, Phil Stone for his good conditions on Mt Kitchener report, and Natasha Rafo for her Elk Mt run down with alarming snow pit data.
Past Weather
50 to 100 cm of new snow has fallen in the past few days. Extreme SW to SE winds transported a significant amount of snow to NE and NW aspects and on to cross loaded features Saturday. At the tail end of Saturday's storm a short lived bit of rain fell below 1300 m followed by clear cold skies. Sunday saw 5 to 15 cm of new snow fall early in the morning with cool temperatures and low winds.
Weather Forecast
Once again two big snow storms will hit the island this bulletin period, Sunday night Jan 3 into Monday morning Jan 4 and during the day Tuesday Jan 5. Winds will be strong to extreme during these storms, but temperatures will be on the colder side. Monday Jan 4: 15 to 30 cm of new snow falling Sunday night into Monday morning (some of the lower mountain elevations in the southern zones may see a bit of this precip start out as rain due to a slightly higher freezing level/temp). Winds Strong to Extreme SE during the snowfall, dropping to moderate SW. Temps at 1500 m 0 to -5 for central/north island, and + 2 to -4 for south. Freezing levels 1200 dropping to 900 m for central and north, 1700 dropping to 900 m for south.Tuesday Jan 5: 30 to 70 cm of new snow during the day. Winds extreme to strong SE. Temps at 1500 m 0 to -4. Freezing levels 800 to 900 m. Wednesday Jan 6: 5 to 15 cm of new snow. Winds Light to moderate SW to variable. Temps at 1500 m -2 to -5. Freezing levels 1000 to 800 m.
Terrain Advice
Avoid avalanche terrain after the snow storm Sunday night Jan 3 and during/after the large snowfall coming Tuesday during the day Jan 5. Winds during these two snowfalls will be strong to extreme from the SE, so NW slopes will be especially dangerous due to wind loading.
Snowpack Summary
On average a meter of snow has fallen since Dec 29. The majority of this new snow has fallen with warm temps so it has been moist heavy snow. From approx 1300 m down a bit of rain has mixed in with these snow events. Above 1300 m it has all been snow. Our typical island snowpack did a great job of healing well after the big storms. Conditions certainly seemed to stabilize by Sunday Jan 3 on SE to SW aspects, while the NE to NW aspects (where there was significant wind loading from Saturday Jan 2) seemed to be slower to heal and even saw natural avalanche activity.
Snowpack Details
- Surface: 5 to 15 cm of new low density powder in sheltered areas, wind effected snow in open zones and ridgetops.
- Upper: 1300 m and below a thin rain crust over storm snow, above 1300 m settling storm snow.
- Mid: Well settled with some old crusts
- Lower: Well settled
Confidence
Moderate - Many days of field data but at the same time many remote weather stations failed to report.
Problems
Wind Slabs
Wind Slab avalanches are the release of a cohesive layer of snow (a slab) formed by the wind. Wind typically transports snow from the upwind sides of terrain features and deposits snow on the downwind side. Wind slabs are often smooth and rounded and sometimes sound hollow, and can range from soft to hard. Wind slabs that form over a persistent weak layer (surface hoar, depth hoar, or near-surface facets) may be termed Persistent Slabs or may develop into Persistent Slabs.
Loose Dry
Loose Dry avalanches are the release of dry unconsolidated snow and typically occur within layers of soft snow near the surface of the snowpack. These avalanches start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. Other names for loose-dry avalanches include point-release avalanches or sluffs.