Posted Danger Ratings are for the northern part of the region. A storm may pass through the Coquihalla area on Monday night and Tuesday. Pay close attention to local weather conditions and be prepared to back off to simple terrain.
Confidence
Moderate - Forecast snowfall amounts are uncertain on Tuesday
Weather Forecast
On Tuesday expect generally overcast skies with isolated flurries. On Wednesday a Pacific system will bring 5-15cm of new snow to the region. Light flurries are forecast for Thursday. Ridgetop winds will be light on Tuesday, and then become moderate and southwesterly with Wednesday's precipitation. Freezing levels should hover between 1200 and 1300m for the forecast period.
Avalanche Summary
No new avalanches have been reported, but this may speak more to a lack of observations rather than actual conditions.
Snowpack Summary
On Sunday night the region received up to 15cm of new snow with highest amounts falling in the northern parts of the region (areas accessed from the Pemberton Valley). Further south in the Coquihalla area, it rained to ridgetop and depending on the current temperature, surfaces are either moist or refrozen. Where it did snow, moderate southerly winds formed soft slabs which seemed most reactive in lee alpine terrain. The new snow overlies a sun crust on sun-exposed slopes, dry settled powder on shady slopes and moist snow below 1800m. Below the new snow the snowpack is strong and well-settled throughout with no notable persistent weaknesses. Cornices are huge and fragile.
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.
Cornices
Cornice Fall is the release of an overhanging mass of snow that forms as the wind moves snow over a sharp terrain feature, such as a ridge, and deposits snow on the downwind (leeward) side. Cornices range in size from small wind drifts of soft snow to large overhangs of hard snow that are 30 feet (10 meters) or taller. They can break off the terrain suddenly and pull back onto the ridge top and catch people by surprise even on the flat ground above the slope. Even small cornices can have enough mass to be destructive and deadly. Cornice Fall can entrain loose surface snow or trigger slab avalanches.
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.