Natural avalanches possible, human triggered probable.
Treeline
Natural avalanches possible, human triggered probable.
Below Treeline
Natural avalanches unlikely.
Alpine
Natural and human triggered avalanches likely.
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.
Regions
South Columbia.
Confidence
Fair - Timing or intensity of solar radiation is uncertain
Weather Forecast
Moderate snowfall is expected to start Wednesday evening and extend throughout the forecast period. Locally heavy accumulations may exist.Ridgetop winds are forecast to be moderate to strong from the southwest on Thursday trending to strong and southwesterly on Friday and Saturday.Freezing levels should stay at about 1350m for the entire period.
Avalanche Summary
No recent avalanche activity to report. We welcome all field observations at [email protected].
Snowpack Summary
Healthy amounts of snow fell throughout last week; however, the more recent break in the weather has given the upper snowpack a chance to settle and gain strength. Over the last few days surface hoar may have been forming, and steep solar aspects may have gone through a melt-freeze cycle creating a sun crust. These newly formed surfaces will be something to watch as the next system moves in to the region on Thursday. Deeper in the snowpack you might find a thin, spotty surface hoar layer between 50 and 85 cm down. As well, the November rain crust now exists over 100cm down in most locations (at treeline and above) and may exist in combination with facets. These layers seem to have been unreactive in recent days, but may have the potential to 'wake-up' with additional loading.The snowpack depth in the alpine ranges from 130-225 cm. Treeline near 150 cm.
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.