Regions
South Coast Inland.
Big changes are hard on the snowpack and can give surprising results. It's time to rein in your terrain use and stick to low consequence areas. If the Duffey zone sees >30cm snow on Tuesday - Wednesday, the danger rating will be HIGH.
Confidence
Low - Timing, track, or intensity of incoming weather system is uncertain
Weather Forecast
We're in an active weather pattern with lots of uncertainty with regard to freezing levels and snow amounts. WEDNESDAY: 15-30 cm (wet) snow (or rain in the south). Freezing levels 1500m and alpine temperatures near -1 in the north (Duffey Lake road) ; Freezing levels 1900m and alpine temperatures to +3 in the south (Coquihalla). Winds moderate gusting strong (40-60 Km/hr) from the southwest. THURSDAY: Flurries (up to 5 cm) ending in the afternoon. Winds easing to moderate from the southwest. Freezing level 1300m and alpine high temperatures to -2 Celsius. FRIDAY: Scattered flurries with some sunny breaks. Freezing levels 1200m and alpine temperatures near -4 in the north and -2 in the south. Winds moderate gusting strong (40-60 Km/hr) from the southwest.
Avalanche Summary
Limited observations but no new reported. I expect a widespread cycle is imminent starting Tuesday.
Snowpack Summary
Sunday night into Monday defied the forecasts and we had a huge snowfall gradient across the region: Manning got 0cm ; the Coquihalla got 12mm rain ; the Duffey got 35cm snow and to cap it off Tenquille Lake got 50cm snow! This new precipitation fell on a wide variety of surface snow conditions:IN THE SOUTH (COQUIHALLA): There was a widespread melt-freeze crust up to 1650m (which probably got soaked with rain). From ridge top down to 1700m there are multiple wind slab layers on southerly aspects from the arctic outbreak events in December & January. These lingering wind slabs will likely remain reactive with the incoming precipitation (whether it falls as rain or snow) so use extra caution in your terrain choice. IN THE NORTH (DUFFEY LAKE RD): The melt-freeze crust from the weekend was limited to steep solar (south) aspects. Wind slabs were found on a variety of aspects (primarily southerly) as far down as 1850m. All the new snow (35cm+) in this zone is not expected to bond well to the old snow interfaces.
Problems
Storm Slabs
Storm Slab avalanches are the release of a cohesive layer (a slab) of new snow that breaks within new snow or on the old snow surface. Storm-slabs typically last between a few hours and few days (following snowfall). Storm-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 Wet
Loose Wet avalanches are the release of wet unconsolidated snow or slush. These avalanches typically occur within layers of wet snow near the surface of the snowpack, but they may quickly gouge into lower snowpack layers. Like Loose Dry Avalanches, they start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. Other names for loose-wet avalanches include point-release avalanches or sluffs. Loose Wet avalanches can trigger slab avalanches that break into deeper snow layers.