Forecast snowfall amounts are uncertain. If you receive less then 15 cm of new snow consider the danger ratings too high.
Confidence
Moderate - Forecast snowfall amounts are uncertain
Weather Forecast
The next Pacific frontal system will reach the Interior tonight spreading moderate precipitation amounts through Wednesday. Average snow amounts range from 15-25 cm by Wednesday afternoon. Ridgetop winds will be moderate-strong from the SW, alpine temperatures -7 and dropping. A split flow in the jet stream will guide subsequent Pacific storms south of B.C. bringing mostly dry and unsettled weather Thursday and Friday. The next storm will move onshore sometime Saturday.
Avalanche Summary
On Tuesday, reports indicated mostly sluffing up to size 1 from steeper terrain features.
Snowpack Summary
Up to 10 cm of recent low density snow overlies a variety of weak surfaces including surface hoar and facets. Storm and wind slabs are expected to build with forecast snow on Wednesday. The upper snowpack is generally loose and unconsolidated due to the current lack of slab properties, however there is now up to 30 cm sitting on a mix of surface hoar, facets, and sun crusts that were buried January 4th. In parts of the Purcells, two prominent layers of buried surface hoar continue to be reactive with hard sudden collapse results in snowpack tests down 30-60 cm. The mid and lower snowpack is generally well settled and strong.
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.
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.