Avalanche Forecast

Issued: Mar 9th, 2021 4:00PM

The alpine rating is moderate, the treeline rating is moderate, and the below treeline rating is low. Known problems include Wind Slabs and Persistent Slabs.

Avalanche Canada mconlan, Avalanche Canada

Increasing wind has the potential to form new wind slabs.

Summary

Confidence

High -

Weather Forecast

TUESDAY NIGHT: Clear skies, 40 km/h north wind, alpine temperature -7 C.

WEDNESDAY: Clear skies, 20 to 40 km/h northeast wind, alpine temperature -7 C.

THURSDAY: Increasing clouds with afternoon snowfall, accumulation 5 cm, 60 km/h southwest wind, alpine temperature -6 C.

FRIDAY: Cloudy with snowfall, accumulation 30 to 50 cm, 30 to 60 km/h southwest wind, alpine temperature -5 C, freezing level 800 m.

Avalanche Summary

A persistent slab avalanche was triggered on Monday along the Skeena corridor/Highway 16 west of Terrace, releasing on the persistent weak layer described in the Snowpack Summary. Otherwise, no new avalanches were observed.

Snowpack Summary

Moderate to strong northerly wind is forecast Monday night, which could load atypical slopes in exposed terrain. Wind slabs have the potential to form anywhere snow is available to be transported. In sheltered terrain, around 30 cm of soft snow may be found.

Around 100 to 200 cm overlies a persistent weak layers buried in mid-February that may still be a concern in parts of the region. The layer consists of feathery surface hoar crystals in areas sheltered from the wind and sugary faceted grains that formed during February's cold snap. Avalanche activity on this layer has mostly occurred west of Terrace along Highway 16 in the past week, but the layer could still be of concern anywhere it exists.

There are currently no layers of concern in the mid and lower snowpack.

Terrain and Travel

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

Problems

Wind Slabs

An icon showing Wind Slabs

New wind slabs may form at higher elevations due to northerly wind. This means that slabs may be found on southerly slopes, which is atypical for the region. Look for signs of instability and be cautious if you enter steep features.

Aspects: East, South East, South, South West, West.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Persistent Slabs

An icon showing Persistent Slabs

Around 100 to 200 cm of snow may overly a persistent weak layer buried in mid-February. The likelihood of triggering the layer may be decreasing as the days progress, but the consequence of doing so would be high.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Unlikely - Possible

Expected Size

2 - 3

Valid until: Mar 10th, 2021 4:00PM