Avalanche Forecast

Fair - Forecast snowfall amounts are uncertain

Synopsis: A Pacific frontal system approaching the coast will spread clouds and precipitation into the Purcells over the next few days.Thursday: Cloudy with flurries, some parts of the region may receive 10 to 15 cm of precipitation. No overnight freeze, freezing levels up to 1400m, Winds moderate, gusting to strong from the south west.Friday: Cloudy with flurries. Some parts of the forecast area may get up to 20 cm of precipitation. No overnight freeze and freezing levels may go up to 1600m. Winds moderate, gusting to strong from the south west.Saturday: Cloudy with flurries. 5 to 10 cm of precipitation in the forecast for the region, daytime freezing level around 1800m, overnight freezing level may drop to valley bottom in some parts of the forecast area, winds, light to moderate from the south west.

Reports of natural avalanche activity have dropped off, but explosive testing is still producing large avalanches, most stepping down to known persistent weak layers. One size 3 natural reported on a north aspect was initiated in extreme steep terrain and stepped down to a deep persistent week layer. We expect to see natural avalanche activity rise with snow and winds associated with the incoming storm system on Thursday and Friday, along with periods of sun and increased air temperatures later in the week.

Up to 50cm of new snow has fallen in the central part of the region in the last storm, with lesser accumulations in the eastern part of the forecast region.. This new snow is settling well, but has also been formed into wind slabs on the lee sides of ridge crests by strong westerly winds.Numerous crusts can be found in the upper 60cm of the snowpack on south facing slopes. The March 15 crust/surface hoar interface is down approximately 50-80cm in most parts of the forecast area. At 90-120cm below the surface you may find surface hoar and crusts that were buried at the beginning of March. This interface is still touchy in some areas, particularly in the north of the region and continues to produce sudden planar failures in compression tests.The deeper facet/crust persistent weakness buried at the beginning of February, now down 120 - 200cm, has proven to be reactive and should not be trusted. An avalanche on any of these deeper, persistent interfaces would be large and destructive. Weak basal facets exist in many areas, but without a large load, triggering is unlikely.