Avalanche danger can rise very quickly with warming and solar radiation. Be aware of changing conditions and overhead hazards. Terrain choices and timing can be critical.
Confidence
Fair - Due to the number of field observations
Weather Forecast
Tonight and Monday: The ridge of high pressure bringing clear and warm conditions remains over the province. Clouds will start building as a low pressure system approaches later in the day. Expect freezing levels to be near 2500 m and light to moderate North West winds.Tuesday: A trace of precipitation is forecasted with light North West winds, freezing levels going from 1200 m at night and rising to 1500 m during the day. Wednesday: Mainly cloudy, a possibility of light precipitation, freezing levels around 1700 m.
Avalanche Summary
Natural loose dry avalanches up to size 2 were reported in Waterton Lakes area. These would have initiated in the new snow sluffing on the underlying crust on shaded aspects in the alpine. Small wet loose avalanches were also reported on the solar aspects in the same region.
Snowpack Summary
Yesterdays light accumulation (~15 cm) is sitting on a crust in most places. Todays above freezing temperatures up to ~2000 m and intense solar radiation would have contributed to the creation of another melt-freeze crust on all aspects below this elevation and higher up on solar aspects. Snow stability is expected to decrease as the day progresses tomorrow, weakening the fresh windslabs and cornices in the alpine. The deep facet/crust persistent weakness buried at the beginning of February (now down up to 80-100 cm) should stay on your radar, especially on all alpine slopes that will see the intense sun tomorrow. Any activity at this interface would be large and destructive.
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.
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.
Deep Persistent Slabs
Deep Persistent Slab avalanches are the release of a thick cohesive layer of hard snow (a slab), when the bond breaks between the slab and an underlying persistent weak layer deep in the snowpack. The most common persistent weak layers involved in deep, persistent slabs are depth hoar or facets surrounding a deeply buried crust. Deep Persistent Slabs are typically hard to trigger, are very destructive and dangerous due to the large mass of snow involved, and can persist for months once developed. They are often triggered from areas where the snow is shallow and weak, and are particularly difficult to forecast for and manage.