Watch for signs of new wind slab formation on Sunday, especially in any areas which receive more than just light snow flurries. Older, larger wind slabs may also still remain reactive to human triggering in isolated areas. Seek out sheltered terrain to avoid the problem and for better riding opportunities in softer snow.
Watch for signs of new or recently formed wind slabs. Any areas which receive more than just light flurries on Sunday may see new wind slab formation.
Larger, older wind slabs that overlie a weak layer may still remain reactive to human triggering in some areas so extra caution is warranted in leeward terrain features.
On Friday, ski cutting was triggering size 1 loose dry avalanches in steep terrain. A small skier-triggered persistent slab was also reported failing on a layer of surface hoar from late January in a below-treeline feature southwest of Nelson. This appears to be an isolated event in the region but a good reminder that weak layers may remain reactive in isolated areas.
New snowfall will bury a highly variable snow surface which may consist of any of the following: a widespread layer of large surface hoar in wind-sheltered terrain, wind slabs or wind-pressed snow in exposed terrain, and sun crusts on steep solar aspects. A slightly older layer of large surface hoar may be found down another 20-30 cm below the old snow surface.
The middle of the snowpack is generally well consolidated and stiff but does contain some old persistent weak layers. These layers have not produced avalanches in quite a long time and are not currently a concern like the regions to the north, but could wake up with significant storm loading or warming.
The lower snowpack consists of a layer of weak, sugary crystals that have been slowly gaining strength and don't currently appear to present the same problem as the regions to the north and east. However, we continue to track the layer and watch for any signs that it might wake up and produce very large avalanches.
Saturday night
Clear and dry with increasing cloud cover overnight, moderate NW wind, treeline low around -12 ˚C.
Sunday
Light snow flurries up to 5 cm, moderate to strong SW wind, treeline high around -5 ˚C.
Monday
Light snowfall continuing overnight up to 10 cm, with a break expected Monday morning before the next storm pulse arrives Monday afternoon, moderate to strong W-NW wind, treeline high around -3 ˚C.
Tuesday
Snowfall 15-25 cm overnight and another 10-25 cm during the day, strong SW wind, easing in the afternoon, treeline high around -5 ˚C.
More details can be found in the Mountain Weather Forecast.
