Natural avalanches possible, human triggered probable.
Treeline
Natural avalanches unlikely, human triggered possible.
Below Treeline
Natural avalanches unlikely.
Alpine
Natural and human triggered avalanches likely.
Treeline
Natural and human triggered avalanches likely.
Below Treeline
Natural avalanches unlikely.
Alpine
Natural and human triggered avalanches likely.
Treeline
Natural avalanches possible, human triggered probable.
Below Treeline
Natural avalanches unlikely.
Regions
South Coast.
This Will be a Week of Dubyas: Windy, Wet and Warm! Expect increasing hazard and widespread natural avalanche activity by Tuesday.
Confidence
Fair - Due to the number of field observations
Weather Forecast
Monday: Cloudy with rain or snow increasing in intensity later in the day. The freezing level is around 1800-2000 m and winds are 30-50 km/h from the S-SW. Tuesday: Rain, heavy at times. The freezing level could climb as high as 2300-2500 m and winds could be gusting close to 100 km/h from the south. Wednesday: Continued heavy rain or snow. The freezing level remains above 2000 m and southerly winds should keep cranking.
Avalanche Summary
No new reports of avalanches but I expect this will be an active week. A natural avalanche cycle is likely with potential for some large, deep slides. Please let us know what you're seeing out there at [email protected].
Snowpack Summary
Around 10-15 cm of moist new snow now covers the previous variable snow surface that consisted of facets (dry sugary snow) and surface hoar in sheltered areas, or pockets of old wind slab and an ice crust in open wind-exposed terrain (depending on aspect). Fresh new wind slabs may have formed in open north and east facing slopes, especially below ridges and behind terrain features in the alpine. There are probably a couple notable crusts in the upper to mid snowpack. The deeper crust may be associated with a weak layer of facetted snow, but may be limited to slopes at and above treeline. One recent snowpack test on this layer in the northwest part of the region produced a sudden "pops" result down 80 cm on a north aspect at treeline. Snow pack depth and snow quality drastically diminishes as you drop below treeline.
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.
Loose Wet
Loose Wet avalanches are the release of wet unconsolidated snow or slush. These avalanches typically occur within layers of wet snow near the surface of the snowpack, but they may quickly gouge into lower snowpack layers. Like Loose Dry Avalanches, they start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. Other names for loose-wet avalanches include point-release avalanches or sluffs. Loose Wet avalanches can trigger slab avalanches that break into deeper snow layers.