We are at the end of our regular forecast season however AVALANCHE HAZARD WILL PERSIST. Generally, hazard will be higher with heating from rain or sun and will be lowest during cool periods. Spring storms may also bring additional snow.
Weather Forecast
NOT PROVIDED FOR THE EXTENDED PERIOD. 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 and when 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
The storm that ended on Tuesday brought 30 to 70cm of low density snow over the previous April 7 and 11 crust layers. The sun came out Wed and rapid heating has formed surface crusts on most slopes except for high steep North. Since Wednesday ridge top winds from the South have built windslabs treeline and above.
Avalanche Summary
A few slabs out of open terrain near treeline were seen in the last two days on East and North aspects. A great deal of loose dry activity occurred during and immediately following the last storm but this activity has settled down with the heating. Loose wet activity picked up with the heating and this will likely remain the dominant concern.
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.
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.