North Columbia

Fresh snow from the past week is capable of producing large avalanches, especially on wind-loaded terrain features.

Moderate - on Sunday

SUNDAY: Flurries intensifying throughout the day with 5-10 cm of snow by the afternoon and then another 5-10 in the evening, moderate southwest wind, freezing level up to 1000 m, and alpine high temperatures near -6 C.MONDAY: Mostly cloudy with light wind, freezing level up to 800 m, and alpine high temperatures near -8 C.TUESDAY: Cloudy with isolated flurries, light wind, freezing level up to 1200 m, and alpine high temperatures near -5 C.

Friday's storm caused a natural avalanche cycle with numerous size 1-2 avalanches in the top 20-30 cm of new snow. Storm slabs were also reactive to skiers, producing several size 1 avalanches on small terrain features on various aspects.Storm slabs avalanches have been reported on a regular basis since Tuesday's storm. Natural avalanches up to size 3 were reported from Tuesday's storm on all aspects from 1900-2800 m. South and west aspects were the most reactive with slabs running on the recently buried late-March crust. In the days following the storm, several size 2 skier and remotely (from a distance) triggered storm slab avalanches were reported. On Wednesday, most human-triggered avalanches were on south and west aspects in the alpine, while activity on Thursday was mostly on east aspects at treeline. Skier triggered slabs were mostly 30-50 cm thick and ran on the late-March layer.

Another 20-30 cm of snow on Friday brings the weekly total throughout the region to 40-80 cm. Strong west winds have redistributed the snow in alpine and treeline terrain.The storm snow sits on an interface buried in late-March that consist of crusts below 1900 m and on south aspects, and surface hoar on shaded aspects at higher elevations.A deeper layer buried mid-March is now 60 to 90 cm below the surface, and is similar to the late-March interface.Deeper persistent weak layers from January and December are still being reported by professional observers, but are generally considered dormant.