Regions
Northwest Coastal.
Confidence
Fair - Forecast snowfall amounts are uncertain on Saturday
Weather Forecast
A warm front is forecast to move over the north coast on Friday night, bringing moderate to heavy precipitation and strong westerly winds. The winds are expected to peak at about 80 km/hr sometime in the early morning. Expect about 15-20 cm of snow overnight and another 10-15 cm during the day on Saturday. The freezing level on Saturday should lower to about 600 metres. Snow is expected to continue on Sunday bringing another 5-10 cm and strong westerly winds. Temperatures are expected to drop by Monday morning as a ridge of high pressure builds over the region.
Avalanche Summary
A couple of size 1.0 avalanches were reported where the recent snow failed on a sun-crust. Natural avalanches up to size 2.5 occurred Wednesday afternoon from mid-low elevation terrain. Sluffing is occurring from steep terrain. Backcountry travel requires local knowledge, extensive experience and training. The obvious clues that show snowpack instability may not be there. You need to dig deep, do your detective work and make good decisions
Snowpack Summary
Due to changing winds, wind slabs can be found on N-NE aspects and S-SW aspects in the alpine on exposed slopes at treeline. Currently, up to 60cm of snow sits over the mid February interface. This interface is variable, it consists of a strong melt freeze crust below 1000m, above 1000 m exists facets, surface hoar (in more sheltered areas), sun crust or wind press. The surface hoar is not widespread but is responsible for much of the larger avalanches that occurred earlier this week. This layer should be on your radar, as it's susceptible to rider triggers. With forecast wind, snow and rising freezing levels this layer may show its wrath again. It's a good time to play conservatively. Below this, the mid and lower snowpack is well settled and strong.
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.
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.