North Columbia

Human triggered avalanches are likely this weekend, especially on slopes getting hit by the sun.

High -

SATURDAY: Sunny with light west wind, freezing level up to 900 m, and alpine high temperatures near -8 C.SUNDAY: Cloudy with flurries increasing throughout the day (5-15 cm of snow) with moderate west 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.

Preliminary reports from Friday suggest another round of natural avalanche activity occurred during Friday's storm.Storm slabs avalanches have been reported on a regular basis since Tuesday's storm. During the Tuesday storm, natural avalanches up to size 3 were reported 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 have been 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. See the recent MIN reports from Glacier National Park for some examples.Recent explosive control has also produced size 2-3 storm slabs up to 100 cm thick on a range of aspects.

Another 15-30 cm of snow on Friday brings the weekly total to 40-80 cm.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.