This is the end of our regular forecast season. Avalanche hazard will persist. Hazard will be higher with heating from rain or sun and will be lowest during cool periods. Spring storms may also bring a return to winter at upper elevations.
Weather Forecast
None provided for the extended period however visitors may call Waterton Lakes National Park Reception on weekdays at 403 859 2224 for more detailed information. Generally: watch freezing levels closely to determine where heating and weakening of the snowpack is likely by the sun and rain. If more snow arrives watch the bond to the surface crusts.
Snowpack Summary
A surface crust exists on all aspects and at all elevations. The strength of this crust varies with location as it freezes with cooling and weakens with heating. In thin snowpack areas weak layers persist that were created by earlier faceting of mid and basal snow. Weak moist snow may fail as point releases or as slabs over crusts or weak layers.
Avalanche Summary
With strong solar inputs a daily cycle of superficial LOOSE WET AVALANCHES spread to affect all elevations and aspects earlier this week. This same heating also caused many CORNICE FAILURES. A few notable slabs were triggered by cornice failures (large loads) in THIN SNOWPACK AREAS where weak snow has developed in the mid and lower snowpack.
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.
Wet Slabs
Wet Slab avalanches are the release of a cohesive layer of snow (a slab) that is generally moist or wet when the flow of liquid water weakens the bond between the slab and the surface below (snow or ground). They often occur during prolonged warming events and/or rain-on-snow events. Wet Slabs can be very unpredictable and destructive.