The hazard will increase on south facing slopes during afternoon warming. Solar radiation could be enough to trigger stubborn persistent slabs or cause cornice failures.Conservative route selection is critical at this time.
Summary
Confidence
Fair - Timing or intensity of solar radiation is uncertain
Weather Forecast
Synopsis: The weather pattern is generally stable with a weak northwesterly flow. Some convective flurries may happen in the afternoon.Wednesday: Sunny with a few cloudy periods and possibility of isolated flurries. Freezing level at valley bottom overnight, rising to 1500m in the afternoon, winds light from the south west.Thursday: Cloudy with flurries, some parts of the region may receive 5 cm of precipitation. No overnight freeze, freezing levels up to 1800m, Winds generally light, south west.Friday: Sunny with cloudy periods and flurries. Some parts of the forecast area may get up to 10 cm of precipitation. No overnight freeze and freezing levels may go up to 2100m. Winds light, south west.
Avalanche Summary
Recent reports of avalanches from size 1.5 to 2.5, on north and northwest aspects. For the most part consisting of soft slabs from recent storm snow with winds. Of note are several size 2 avalanches triggered by cornice failures dropping into steep terrain in the alpine and at tree-line. Expect to see natural avalanche activity rise with extended periods of sun and increased air temperatures later in the week.
Snowpack Summary
Up to 50cm of new snow has fallen in the central part of the region in the last 3 days (5-10cm in the northern and southern parts of the region). This new snow is settling well, but has also been formed into soft wind slabs immediately lee of ridge crests by recent 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 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.
bcorrigan,
Avalanche Canada
