High freezing levels and strong solar inputs are contributing to widespread avalanche activity. For more details, see Special Avalanche Warning (SPAW) above.
Recent storm snow and extreme winds have added to older slabs. Now up to 60cm thick, these slabs sit over numerous weak layers of facets, surface hoar, or sun crust. Human triggering will remain likely over the short term.
Clear skies and warm temperatures have been a driver for some natural activity (see avalanche table) and smaller, loose, wet avalanches out of steep terrain. These smaller slides could trigger the persistent layers, resulting in bigger slides.
The recent storm has added load to an already shallow and weak snowpack. With this additional weight and warmer temperatures, there may be a reawakening of this problem in isolated areas. Areas of concern include thin, shallow, and rocky slopes.
Natural avalanche activity continued on Saturday due to warm temperatures and strong solar inputs throughout the day. Widespread loose wet avalanches were observed on most steep, solar-exposed terrain. Several cornice failures were reported at local ski resorts, triggering persistent slabs up to size 2.5.
Avalanche control on Mount Whymper resulted in numerous releases, up to size 3.5, triggering the January 30th persistent problem.
Newly formed crust on solar aspects overlays previous formed slabs up to 60cm thick. The slabs sit on weak layers of facets, surface hoar or sun crust formed in late Jan and Feb.
The mid-pack is generally faceted, while depth hoar and crusts form an even weaker base. The snowpack is the weakest in eastern areas where snow depths are low. In these areas, the basal weaknesses should be carefully considered.
The ridge of high pressure will persist through Sunday, with freezing levels at 2200m, light to moderate winds, and clear skies. Late Sunday night, an upslope weather system from the east will move in, bringing cooler temperatures and precipitation, primarily affecting the eastern parts of the forecast region. Snow accumulation for Monday is expected to range from 2 to 10 cm.
