Avalanche Forecast

Keep an eye on changing conditions this weekend, as the forecast is uncertain. Weather models are having trouble resolving this storm. With each successive model run, the snowfall amounts are decreasing, and it now looks like the juiciest part of the storm may pass a little south of the region.

Saturday Night: Cloudy. 0-5 cm of snow expected. Strong south ridgetop winds, trending to moderate by the morning. Freezing level between 500 m and 1000 m in the southern half of the region. Alpine high around -3 °C.

Sunday: Mostly cloudy. 2-5 cm of snow expected, possibly a bit more in the far south of the region. Moderate south ridgetop winds, trending to strong southwest at higher elevations. Freezing levels around 750 m. Alpine temperature around -3 °C.

Monday: Partly cloudy. 0-5 cm of snow expected overnight (possibly a bit more in the far south of the region), and another 0-2 cm through the day. Moderate southeast ridgetop winds. Freezing level around 1000 m.

Tuesday: Mostly cloudy. 2-7 cm of snow expected overnight, another 5 cm through the day. Once again, there could be more in the far south of the region. Strong southwest ridgetop wind. Freezing level around 1000 m.

On Saturday, a professional operation northeast of Terrace reported very small 10-15 cm deep windslabs sliding on an old, wind effected surface, on steep convex rolls at treeline. As light snowfall and moderate to strong wind continue, we expect that similar, but larger, reactive windslabs will form.

On Friday, a professional operation west of Terrace reported a couple of naturally triggered cornice avalanches up to size 2 on a southeast aspect in the alpine. 

Thursday to Saturday, many small, naturally triggered, loose dry avalanches in steep and/or sun exposed terrain were reported across the region.

On Thursday, a professional operation east of Stewart reported two large avalanches triggered by natural ice fall in steep terrain. 

Light to moderate flurries continue. Moderate to strong southeast through southwest ridgetop winds are redistributing 

the new snow snow, and 10-30 cm of recent, low density snow. Expect reactive windslabs to form on lee slopes over a variety of old, generally wind effected surfaces. In sheltered areas, the new snow could be falling on surface hoar up to 20 mm, so we'll be keeping an eye on this potential weak layer as the snow load above it increases.

The upper snowpack appears to be starting to bond to a rain crust buried in mid-February, but we are not ready to completely trust that bond until it has weathered some significant warming or precipitation. 

Depth of the rain crust is quite variable across the region, from 20-100 cm, and can even be found on the surface in very wind exposed terrain. This obvious, 10-30 cm thick crust effectively caps the underlying snowpack, making human triggering of avalanches on deeper weak layers very unlikely.

• Fresh wind slabs will likely form throughout the day, diligently watch for changing conditions.
• Back off if you encounter whumpfing, hollow sounds, or shooting cracks.
• Watch for wind-loaded pockets especially around ridgecrest and in extreme terrain.
• Highmark or enter your line well below ridge crests to avoid wind loaded pillows.
• Use caution above cliffs and terrain traps where even small avalanches may have severe consequences.