Use caution on north facing slopes in the alpine: riders are triggering a reactive wind slab.
Its spring and conditions vary greatly depending on aspect, elevation and time of day.
Strong winds have formed wind slabs on lee slopes at treeline and in the alpine. This layer is heavy new snow sitting on a crust and it's able to pick up mass in steep terrain. On high alpine North facing slopes, this wind slab sits on a layer of surface hoar and is producing size 2-2.5 avalanches!
Intense spring sun will trigger wet loose avalanches in a weak snowpack below treeline. Rider triggering is also possible, use caution in steep terrain and around terrain traps.
On Friday there was a backcountry report of skier triggered sz 2 wind slab on the Dome glacier at 2450 m on a NE asp. This avalanche likely failed on a layer of surface hoar down 10-30 cm.
Check out this MIN from Friday for another skier accidental, sz 2.5 with involvement on this interface. Dig down and have a look for this layer before jumping into large or committing features.
Saturday our field team found a reactive storm slab producing size 1.5s on the steepest part of Balu Pass.
Daily melt/freeze cycles are affected the surface of the snowpack on solar slopes and all aspects BTL. Recent storm snow has formed a slab on lee features, with a recent crust as a bed surface. High alpine, north facing slopes still hold dry snow. A buried surface hoar layer exists in sheltered alpine areas above ~2300m. This layer is reactive and catching people off guard.
Use caution below treeline, conditions are variable and challenging travel exists.
Unstable, moist spring weather continues with a mix of sun, cloud and rising freezing levels early in the week.
Tonight Cloudy w/clear periods. Alp low -9°C. Ridge wind NW 20-40. Freezing Level (FZL) 500m.
Sun Mix sun & cloud. Ridge wind W 15-25. FZL 1800m.
Mon Mix sun & cloud, precip: nil. Alp high -4°C. Ridge wind SW 15-30. FZL 2300m
Tues Sun, cloud, and flurries. Alp high -1°C. Ridge wind W 10-25km/h. FZL 2000m.
