North Columbia

Cooler temperatures and snowfall will shift concerns to new snow instabilities for Tuesday. Then it's back to our daily sunshine and warming pattern for Wednesday and beyond.

Moderate - Forecast snowfall amounts are uncertain

Monday night: Mainly cloudy with isolated flurries and a trace of new snow. Light southeast winds.Tuesday: Cloudy with flurries bringing 5-15 cm of new snow, continuing overnight. Moderate southwest winds. Alpine high temperatures around -4 with freezing levels to 1500 metres.Wednesday: A mix of sun and cloud with isolated flurries and a trace of new snow. Variable new snow totals of 10-25 cm. Light northeast winds. Alpine high temperatures around -3 with freezing levels to 1800 metres.Thursday: Sunny with cloudy periods. Light north winds. Alpine high temperatures around -1 with freezing levels to 1900 metres.

The wet loose avalanche cycle from last Sunday to Friday diminished as cooler, seasonal temperatures returned to the mountains on Saturday. Evidence of the cycle is widespread at all elevations, with recent avalanches up to size 3 found mostly on southeast to southwest aspects. A few large slab avalanches were also triggered on other aspects, with many of them running to valley bottom.Looking forward, cooling temperatures and inbound snowfall will shift concerns to new snow instabilities over the near term. These are likely to present initially as small new wind slabs forming on lee slopes at higher elevations. The re-emergence of the sun from Wednesday onward will shift us back into a spring pattern of loose wet avalanche concerns increasing with sun and warming each day.

Light new snow amounts have begun to accumulate above a surface of melt-freeze crust in most areas above 1500 metres, with the exception of north aspects above 2000 metres, where it may bury settled dry snow. Below about 1500 metres, new snow will land on variably isothermal (slushy) and crusty surfaces. The remainder of the snowpack is generally consolidated and strong. Exceptions may exist on northerly aspects above 2000 m, where a gradually strengthening layer of faceted grains buried 40 to 60 cm deep may still be preserved below an overlying slab of old and hard wind-affected snow.