Avalanche Forecast

SATURDAY NIGHT: Snow, 5-15 cm, strong to extreme southwest wind, temperature low -6 C, freezing level rising to 1000 m.

SUNDAY: Snow, 10-30 cm, strong to extreme southwest wind, temperature high 0 C, freezing level at 1300 m.

MONDAY: Mostly cloudy, 5-10 cm new snow, strong southwest wind, temperature high -2 C, freezing level at 800 m.

TUESDAY: Sun, cloud, and isolated flurries, moderate gusty west wind, temperature high -5 C, freezing level at 400 m.

We have had limited field observations in the past few days, however I suspect that winds have redistributed loose snow forming wind slabs in leeward terrain.

Several natural wind slab avalanches up to size 2 were observed in the alpine and at treeline on steep east facing slopes on Wednesday. A few small dry and wet loose avalanches out of steep solar aspects were reported. On Tuesday several small dry loose avalanches were reported as well as natural wind slab avalanches up to size 2.5 in the southwest of the region.

Wind slabs have been reactive to human triggering in wind loaded and cross loaded features over the weekend. Most ski cut results have been of size 1 to 1.5. On Saturday hard wind slabs were easy to trigger in the Crater Lake area as evidenced by this MIN.

In the Babine area a field team noted numerous size 1-2 wind slabs in the alpine on Saturday from the past 36 hours. They also posted this MIN from the Onion. This is in line with other avalanche observations from the outflow wind cycle like this size 2 near Miller Creek.

10-30 cm fresh snow overlies hard slabs, scoured slopes and sastrugi where outflow effects have been the strongest. Southwesterly winds have developed slabs in leeward terrain. In sheltered areas, previous cold temperatures promoted surface faceting, fresh snow overlies low density facets in sheltered areas. The late January interface is down 40-60 cm consisting of isolated surface hoar in sheltered locations, and previous wind affected layers in exposed areas. On solar aspects, a buried sun crust can be found in places as well.

The lower snowpack has two decomposing crust layers. The upper crust is 70-140 cm deep and continues to show occasional hard, sudden results in snow pits. The deeper crust at the bottom of the snowpack is more prevalent in shallow snowpack ranges. These deep persistent layers seem to be dormant under the current conditions, but shallow rocky slopes should still be carefully assessed and approached with caution. 

• Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
• Watch for signs of instability like whumpfing, hollow sounds, shooting cracks or recent avalanches.
• Potential for wide propagation exists, fresh slabs may rest on surface hoar, facets and/or crust.
• Pay attention to cornices and give them a wide berth when traveling on or below ridges.