Natural avalanches possible, human triggered probable.
Treeline
Natural avalanches possible, human triggered probable.
Below Treeline
Natural avalanches unlikely, human triggered possible.
Alpine
Natural avalanches possible, human triggered probable.
Treeline
Natural avalanches possible, human triggered probable.
Below Treeline
Natural avalanches unlikely, human triggered possible.
Alpine
Natural avalanches possible, human triggered probable.
Treeline
Natural avalanches unlikely, human triggered possible.
Below Treeline
Natural avalanches unlikely, human triggered possible.
Regions
Northwest Coastal.
Be aware of the potential for smaller avalanches to step down to deeper persistent weaknesses. A cautious approach to terrain selection is recommended.
Confidence
Moderate -
Weather Forecast
TUESDAY: Mix of sun and cloud, wind light northeast, alpine temperature -8WEDNESDAY: Mix of sun and cloud, wind light east, alpine temperatures -7THURSDAY: Mix of sun and cloud, wind light northeast, alpine temperature -8 More details can be found on theMountain Weather Forecast.
Avalanche Summary
Over the weekend alpine and tree line features were observed running to Size 3.5. Below tree line both storm and glide slab avalanche activity to Size 2 was observed. Numerous loose wet avalanches have also been reported at highway elevations over the past three days. Several avalanches involving the full depth of snowpack to size 3.5 were reported in the Ningunsaw and Bell 2 areas. One was reported a being remotely triggered by a skier from a distance of 150m away.
Snowpack Summary
A storm that impacted the region over Friday to Sunday morning delivered approximately 60-110 cm of new snow to the mountains, with the greatest depths accumulating in coastal areas. Strong to extreme southwesterly winds accompanied the storm while lower elevations saw precipitation falling as rain. It can be expected that 70-130 cm have accumulated above above the latest buried surface hoar layer from January 23rd. This surface hoar was previously reported growing up to size 10mm at tree line and below. It may be sitting on a crust below 1100m. Although storm slab activity has captured our attention, there continue to be several other surface hoar layers of concern from early January and Christmas. Some reports have shown these persistent weak layers to be rounding and bonding, however recent reports have shown hard sudden results in snowpack tests.
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.