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.
Alpine
Natural avalanches unlikely, human triggered possible.
Treeline
Natural avalanches unlikely, human triggered possible.
Below Treeline
Natural avalanches unlikely.
Regions
South Coast Inland.
More snow on Monday, with the highest amounts in the south of the region, will keep the hazard at Considerable. Observe for the bond of the snow with the underlying surface before committing into avalanche terrain.
Confidence
Moderate - Intensity of incoming weather systems is uncertain
Weather Forecast
MONDAY: Cloudy with snowfall, accumulation 10 to 20 cm with the most in the south of the region, light to moderate southeast winds, alpine temperature -5 C, freezing level 1300 m.TUESDAY: Cloudy with light snowfall, accumulation 2 to 5 cm, light west winds, alpine temperature -6 C, freezing level 1400 m.WEDNESDAY: A mix of sun and clouds, light south winds, alpine temperature -7 C, freezing level 1300 m.
Avalanche Summary
Numerous small wind slab avalanches were triggered naturally and by skiers on Saturday, 20 to 40 cm deep and on northerly aspects in treeline and alpine terrain. These were generally running within the recent storm snow on a melt-freeze crust. Check out the MIN report here for some observations on the weekend.
Snowpack Summary
30 to 50 cm of recent snow has been redistributed by strong south winds, forming reactive wind slabs up to 1 m deep in lee terrain features. Sun, rain, and warm air temperatures on Sunday moistened the snow surface, which will freeze into a melt-freeze crust on all aspects up to at least 1800 m. Snowfall on Monday will fall on these surfaces. On ridges, cornices are reported to be large and fragile.A weak layer consisting of surface hoar, facets, and/or a melt-freeze crust from late March is now buried about 50 to 100 cm. Although this layer is spotty in its distribution and avalanches haven’t been reported on it since early April, professionals are treating it seriously and avoiding terrain because of it. It is mostly likely to be problematic on west, north, and east aspects between 1900 m and 2250 m.The mid and lower snowpack are 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.