Avalanche Forecast

Moderate - Uncertainty is due to the limited number of field observations.

Monday night: No precipitation expected. Moderate winds with potentially strong gusts from the north at mountain/ridge top. Light northerly wind at lower elevations. Temperatures falling to -12 or so overnight.

Tuesday: No precipitation expected. Moderate winds with some strong gusts from the north at mountain/ridge top. Light and variable wind at lower elevations. Afternoon temperatures rise to -5ish. Clear with lots of sun in the alpine, possibly some low cloud.

Wednesday: Flurries possible but no significant accumulation expected. Light and variable winds. Temperatures cool a bit, around -6 to -10. Expect a sunny morning will change to cloudy by afternoon.

Thursday: Flurries but nothing major. Pretty windy from the north. Temperatures -8 to -10 Mostly cloudy.

Loose wet avalanches were observed throughout the weekend on sunny slopes, especially near rocks and at upper elevations where temperatures were warmest and solar radiation effects were strongest. 

A couple of slabs were reported as having scrubbed to the ground in shallow snow in the Wheaton area. A large cornice fall on a shaded slope produced no avalanche in a location where the snowpack was deeper.

As the snowpack cools and tightens, no significant avalanche activity is likely other than the possibility of isolated human triggered wind slabs. I suspect the most likely places where you might trigger something will be on steep, sunward facing terrain where solar radiation might warm things up and loosen bonds in the upper snowpack.

The upper snowpack warmed up over the weekend. Warming was most significant at upper elevations due to a temperature inversion (temperatures at upper elevations were warmer than lower down). Warming was further enhanced on steep southerly aspects where solar radiation was strong, especially in shallow areas and around rocks which concentate the heat from the sun. 

The warming didn't seem to have much of an effect on the wind slabs that formed last week. Deep snowpack areas also fared pretty well. But the surface got warm and wet enough to create unstable moist and wet snow on the surface in the afternoons. There's some evidence that warming increased instability in shallow snowpack areas and cornices may also have become somewhat more unstable.

A cooling trend will strengthen the pack by freezing snow grains together which improves the bonds between layers. Crusts will form where the surface snow became moist or wet during the warming trend. In the short term this will increase overall stability but the crusty surfaces are something to watch when new snow arrives. There's a chance that solar heating might remain a factor on steep sunny terrain features on Tuesday.

• Recent wind has varied in direction so watch for wind slabs on all aspects.