The snowpack is complex and quite variable right now. Buried weak layers remain reactive and conservative terrain selection remains critical.Extra caution is required during the heat of the day, especially on sun exposed slopes and around cornices.
Confidence
Moderate - Timing or intensity of solar radiation is uncertain
Weather Forecast
A ridge of high pressure keeps the region dry Thursday and Friday before a weak storm system arrives Saturday. Thursday is expected to be mainly sunny with light alpine winds from the southwest. Freezing levels are expected to drop below valley bottom overnight and reach 1500-1700m on Thursday afternoon. Friday is expected to be mainly sunny in the morning with increasing cloudiness during the afternoon. Alpine winds are expected to be moderate from the southwest and freezing levels are forecast to potentially reach 2000-2500m. There is still a lot of uncertainty as to how warm it will get on Friday and whether the warm air will make it to the Cariboos. A weak storm front is currently forecast to reach the region Friday overnight bringing 5-10cm of snowfall on Saturday.
Avalanche Summary
On Tuesday, several natural size 1 loose avalanches were reported. Also reported was one natural size 2 loose avalanche from a northwest aspect at 2800m. On Monday, two size 2.5 cornice releases were reported from north aspects.
Snowpack Summary
Surface hoar growth is being reported in sheltered areas as well as near surface faceting. Wind affected surfaces are being reported in the alpine and large cornices are reported to be weak. The surface hoar and/or crust layer from early February is now down 70-90cm and remains reactive in snowpack tests. This layer is expected to become most reactive during the heat of the day, especially on sun exposed slopes.
Problems
Persistent Slabs
Persistent Slab avalanches are the release of a cohesive layer of snow (a slab) in the middle to upper snowpack, when the bond to an underlying persistent weak layer breaks. Persistent layers include: surface hoar, depth hoar, near-surface facets, or faceted snow. Persistent weak layers can continue to produce avalanches for days, weeks or even months, making them especially dangerous and tricky. As additional snow and wind events build a thicker slab on top of the persistent weak layer, this avalanche problem may develop into a Deep Persistent Slab.
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.