Regions
South Coast Inland.
Watch for lingering wind slabs in high north facing terrain. Extra caution is needed around all steep sun exposed slopes as well any slopes exposed to large cornices.
Confidence
Moderate - Timing or intensity of solar radiation is uncertain
Weather Forecast
Mostly sunny conditions are expected on Monday with light to moderate alpine wind from the north. Freezing levels are forecast to drop to around 500 m Sunday overnight and reach around 1500 m on Monday afternoon. Increasing cloud cover is expected on Tuesday with light to moderate alpine wind from the south and freezing levels reaching around 1700 m in the afternoon. Light precipitation is forecast for Wednesday with strong alpine wind from the southwest and freezing levels reaching around 2000 m in the afternoon.
Avalanche Summary
On Saturday, skiers triggered a few size 1 wind slabs in leeward features in the alpine and at treeline in the north of the region. A few natural cornice releases up to size 2.5 were also observed in the north of the region but did not trigger slabs on the slopes below. No new avalanches were reported on Friday. On Monday, wind slabs on northerly aspects in the alpine may still be reactive to human triggering. Natural solar triggered sluffing is expected from steep sun exposed slopes and natural cornice releases are also possible when the sun is shining.
Snowpack Summary
A widespread crust is expected to have formed on all aspects and elevations except for high north facing slopes. Recent strong winds from the south have formed wind slabs in the alpine and have added load to cornices. On sun exposed slopes and at lower elevations, several crusts likely exist in the upper snowpack. In the north of the region, the February persistent weak layers may still be found in the alpine and are down 100-140cm. They include a buried surface hoar layer as well as a crust/facet layer. In the southern parts of the region, the mid and lower snowpack are generally well settled and strong.
Problems
Wind Slabs
Wind Slab avalanches are the release of a cohesive layer of snow (a slab) formed by the wind. Wind typically transports snow from the upwind sides of terrain features and deposits snow on the downwind side. Wind slabs are often smooth and rounded and sometimes sound hollow, and can range from soft to hard. Wind 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.
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.