All bets are off this weekend with regard to stability as the region heats up in a big way. Stick to simple terrain and avoid overhead hazard.
Weather Forecast
An upper ridge is expected to cross the province this weekend ushering in warm spring like temperatures on both Saturday and Sunday. By Monday the ridge should be loosing strength, which will open the door to cool and unsettled weather going into Tuesday. SATURDAY: Freezing level starting at valley bottom then rapidly climbing to around 2000 m by lunch time, moderate west/southwest winds, no precipitation, clear skies. SATURDAY NIGHT: Freezing level holding around 2500 m. SUNDAY: Freezing level staying around 2500 m, moderate southwest winds at ridge top, no precipitation expected. Increasing cloud cover may trap warm air leading to a greenhouse effect. MONDAY: Freezing level hovering around 2100 m for most of the day, light rain possible in the afternoon, light variable winds and broken skies.
Avalanche Summary
On Thursday avalanche observations were limited to small loose dry releases running in the storm snow. On Wednesday explosive control work in the far north of the region produced numerous large to very large persistent slab avalanches on north through east facing features between 2200 m and 2400 m. Cornices were reported to be very touchy and sensitive to triggering. Over the course of the last week we have received many reports of cornice failure (some of them quite large), but no reports of subsequent slab avalanches being triggered when falling cornices impacted slopes below.
Snowpack Summary
On Thursday there was around 15 to 25 cm of new snow at 1700 m. There has been a touch of northeast wind over the last 48 hours which is forming soft wind slabs in upper elevation wind exposed terrain. These wind slabs may be sitting on the mid-March crust, which is down around 20 cm below the snow surface. The early March crust can be found down around 50 cm below the surface. Both of these crusts are reported to be present from valley bottom to around 2300 m, where they begin to disappear. There are thin snowpack areas in the South Rockies region where deeply buried weak layers near the ground remain sensitive to triggering. Huge cornices still hang over many ridge-lines and many are likely teetering on the brink of failure.
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.