Avalanche Forecast

Archived

Feb 16th, 2023–Feb 17th, 2023

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely, human triggered possible.

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely, human triggered possible.

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely, human triggered possible.

Regions

Coquihalla, Harrison-Fraser, Manning, Skagit.

Avalanches are possible in wind-loaded areas at all elevations. Carefully evaluate wind loading as you move through terrain and investigate the bond of wind slabs to the crust below them before committing to an open slope.

Confidence

Moderate

Avalanche Summary

On Tuesday, clear weather allowed operators to see into higher elevations. Evidence of a widespread avalanche cycle from last weekend's storm was observed throughout the region. Several natural cornice and windslab avalanches were observed to size 2.5. Several loose dry avalanches were observed to size 2 out of steep rocky features. These avalanches were all likely caused by past wind loading, warming, or solar input.

Please continue to post your reports and photos to the Mountain Information Network.

Snowpack Summary

Southwest winds continue redistributing 20 cm of available snow into lee features at higher elevations. On steep solar surfaces, you will find a thin melt-freeze crust. In sheltered areas, 20 to 30 cm of recent storm snow remains unconsolidated, this overlies an additional 50 cm of past HST that has settled and is well bonded.

A melt-freeze crust formed in mid-January is now buried up to 80-120 cm deep. At the moment this layer appears to be gaining strength though in isolated areas small facets are still found above the crust. The snow below this layer is consolidating nicely. Buried 120-150 cm is a crust, formed near the end of December.

Snowpack depths are just below seasonal averages. Total amounts range from 150 to 200 cm at treeline, but decrease significantly below 1500 m.

Weather Summary

Thursday Night

Overcast with continued light to moderate snowfall, 5 to 15 cm of accumulation. Winds southwest 30 km/h gusting 50 km/h. Treeline temperatures -2 °C and freezing levels slowly rise to 1200 m.

Friday

Cloudy with very light isolated flurries, 1 to 5 cm of accumulation. Winds southwest 30 km/h easing to 20 km/h. Treeline temperatures -6 °C and freezing levels of 500 m.

Saturday

Overcast with continued light to moderate snowfall, 5 to 15 cm of accumulation. Winds northwest 30 km/h gusting 50 km/h. Treeline temperatures -3 °C and freezing levels 1000 m.

Sunday

Cloudy with very light isolated flurries, 1 to 5 cm of accumulation. Winds northwest 20 km/h gusting to 60 km/h. Treeline temperatures -6 °C and freezing levels of 500 m.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
Avoid freshly wind loaded features, especially near ridge crests, roll-overs and in steep terrain.
Seek out wind sheltered terrain below treeline where you can avoid wind slabs and find great riding.
Be alert to conditions that change with elevation and sun exposure.

Problems

Wind Slabs

Wind Slab avalanches are the release of a cohesive layer of snow (a slab) formed by the wind. Wind typically transports snow from the upwind sides of terrain features and deposits snow on the downwind side. Wind slabs are often smooth and rounded and sometimes sound hollow, and can range from soft to hard. Wind slabs that form over a persistent weak layer (surface hoar, depth hoar, or near-surface facets) may be termed Persistent Slabs or may develop into Persistent Slabs.