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 unlikely, human triggered possible.
Treeline
Natural avalanches unlikely, human triggered possible.
Below Treeline
Natural avalanches unlikely.
Regions
Lizard-Flathead.
Sunshine and rising freezing levels will increase the likelihood of loose wet avalanches and cornice failures. Minimize exposure to sun exposed slopes when the solar radiation is strong.
Confidence
Moderate - Due to the number of field observations
Weather Forecast
THURSDAY: Sunny. Light southwest wind. Alpine temperature +6. Freezing level 2400 m.FRIDAY: Sunny. Light to moderate southwest wind. Alpine temperature +6. Freezing level 2500 m.SATURDAY: Mix of sun and cloud. Strong southwest wind. Alpine temperature +1. Freezing level 1800 m.
Avalanche Summary
Several naturally triggered size 2 storm slab avalanches were reported on north to east aspects, between 1800-2100 m near Fernie on Tuesday. Avalanche reports have been limited due to very few information sources this time of year. If you have been out, please post your observations on the Mountain Information Network (MIN).
Snowpack Summary
Cornices are large and looming. Lingering storm slabs formed by 20-30 cm of recent snow may still be reactive to human triggers; especially in wind affected terrain. This storm snow overlies numerous crusts in the upper 100 cm of the snowpack. The mid-pack is generally well settled and strong.A layer of sugary facets around a crust can be found near the bottom of the snowpack which has been dormant for some time. Large triggers, such as a falling cornice, or a major warm-up to the snowpack could trigger this layer.
Problems
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.
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.
Cornices
Cornice Fall is the release of an overhanging mass of snow that forms as the wind moves snow over a sharp terrain feature, such as a ridge, and deposits snow on the downwind (leeward) side. Cornices range in size from small wind drifts of soft snow to large overhangs of hard snow that are 30 feet (10 meters) or taller. They can break off the terrain suddenly and pull back onto the ridge top and catch people by surprise even on the flat ground above the slope. Even small cornices can have enough mass to be destructive and deadly. Cornice Fall can entrain loose surface snow or trigger slab avalanches.