South Columbia

Areas in the south may get some sun on Monday. Direct sun may spark a new cycle of avalanche activity.

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

Snow eases to light amounts on Monday, then the next pulse begins on Monday night, bringing around 5-10 cm snow through Tuesday with moderate to strong SW winds. Freezing levels are between 1800 m and 2200 m, dropping on Tuesday to around 1600 m and 1200 m by Wednesday.  

On Saturday, a few naturally triggered persistent slabs, size 2-3, were observed. A widespread avalanche cycle ran on Thursday and Friday in response to wet and windy conditions. These were a mix of storm slab, loose wet avalanches and persistent slabs, up to size 3.

Strong winds have shifted recent snow onto lee slopes at high elevations. Rain on Friday soaked the upper snowpack to at least treeline. Two persistent weak layers in the upper metre or so of the snowpack are the main story. The mid-March layer, around 60 cm down, is most reactive where it exists as a crust. Around 80-100 cm down, the mid-February facet/crust interface has also been reactive with large loads like smaller avalanches stepping down, cornice fall or explosives. Both layers are sensitive to triggering and propagate easily, causing very large avalanches.