Avalanche Forecast

Moderate - Timing, track, or intensity of incoming weather system is uncertain

Overcast with light snow, light westerly winds, and freezing levels down to 800 metres overnight. Light snow with increasing southwest winds on Wednesday and daytime freezing levels up to 1600 metres. Light to moderate precipitation (5-10 cm) starting early Thursday with moderate to strong southwest winds and overnight freezing levels around 1300 metres. Freezing dropping back to valley bottoms by Friday morning. A weak ridge is expected to build on Friday, but we are un-certain regarding the amount of sunshine we will see.

An early report on Tuesday of a natural slab avalanche size 2.5 on a southwest aspect at 2200 metres with a wide propagation and depth of about 100 cm, the bed surface was suncrust with melted surface hoar on top. Solar induced loose wet avalanches up to size 2.0 were reported on Monday. On Sunday we had reports of numerous storm slab avalanches size 1.5 from various aspects, with a couple reaching size 2.0 on north aspects. On Saturday a wind event triggered a size 3 avalanche that started near 2300 m, failing on a steep un-skiable east facing piece of terrain. Over the last week we have received 5 reports of very large (size 3) avalanches on north, east and south aspects between 1700 and 2400 m. Some have failed after being hit with a large chunk of falling cornice, others have released without a large trigger.

There is 10-20 cm of moist surface snow that has re-frozen into a crust at all elevations on solar aspects, and up to at least 2000 metres on shaded aspects. Daytime warming continues to melt surface snow, and overnight crust recovery has been variable depending on cloud cover. Large cornices loom over many ridge lines and many are teetering on the brink of failure. Old wind slabs may remain a problem on high elevation north facing features. The make up of the late February persistent weak layer is an aspect dependant mix of surface hoar, facets and/or a thick crust down around 70 to 100 cm below the snow surface. Large triggers like natural cornice fall and explosive control work continue to initiate avalanches failing on this interface. The recent warm to cool temperatures should give the overlying slab a bit of strength, but it has yet to prove itself trustworthy. Unfortunately there's not much of a reliable pattern telling us what exact aspects are most suspect. As a precautionary measure, we recommend remaining suspicious of steep unsupported features at and above treeline.