Avalanche Forecast
Regions: Glacier.
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.
Confidence
Moderate
Avalanche Summary
Backcountry report of skier triggered, sz 2 wind slab on the Dome glacier @ 2450 m on a NE asp. This avalanche likely failed on an isolated layer of surface down 10-30 cm. See MIN on Thursday 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.
Thursday our field team found a reactive storm slab on a steep alpine features, that failed 10-20cm deep and 5m wide.
Snowpack Summary
Falling freezing levels will strength upper snowpack, freezing a series of melt-freeze crusts. Seek high alpine, north facing slopes to find dry snow. Recent storm snow has formed a slab on lee features, with a recent crust as a bed surface. This wind slab is most reactive on lee slopes loaded by southerly winds and where spotty surface exists.
Use caution below treeline, conditions are variable and challenging travel exists.
Weather Summary
Unstable, moist spring weather continues, with falling freezing levels and light snow on Saturday.
Tonight Cloudy w/clear periods Alp low -7°C. Ridge wind light SW. Freezing Level (FZL) 1200m.
Sat Sun, cloud, and flurries. Alp high -6°C. Ridge wind W 25-40km/h. FZL 1600m.
Sun Mix sun & cloud. Ridge wind W 15-30. FZL 1800m.
Mon Clouds with sun, isolated flurries. Alp high -4°C. Ridge wind W 15-30. FZL 1800m
Terrain and Travel Advice
- Watch for newly formed and reactive wind slabs as you transition into wind-affected terrain.
- Look for signs of instability: whumphing, hollow sounds, shooting cracks, and recent avalanches.
- A moist or wet snow surface, pinwheeling, and natural avalanches are all indicators of a weakening snowpack.
Avalanche Problems
Wind Slabs
Strong winds have formed wind slabs on lee slopes at treeline and in the alpine. In isolated pockets on high north aspects, surface hoar is present below the slab. We have limited observations of this interface. In some locations the slab of snow is moist and running on a crust.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood: Likely
Expected Size: 1 - 2.5
Loose Wet
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.
Aspects: All aspects.
Elevations: Treeline, Below Treeline.
Likelihood: Possible
Expected Size: 1 - 2