Avalanche Forecast

Issued: Jan 24th, 2022 4:00PM

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

Avalanche Canada shorton, Avalanche Canada

Email

Be careful around steep wind-affected slopes where it could possible to trigger avalanches on buried weak layers.

Summary

Confidence

Moderate - Uncertainty is due to the complexity of the snowpack’s structure. Uncertainty is due to how quickly the snowpack will recover and gain strength.

Weather Forecast

MONDAY NIGHT: Increasing cloud overnight as freezing level drops to valley bottom, moderate wind from the southwest, treeline temperatures around - 8 C.

TUESDAY: Cloudy skies with some isolated flurries bringing trace amounts of snow, moderate to strong wind from the west, freezing level climbs to 800 m with treeline temperatures around -4 C.

WEDNESDAY: Clear skies except for a possibility of valley cloud, moderate wind from the southwest, an inversion forms with above freezing temperatures between 1500 and 2000 m.

THURSDAY: Clear skies except for a possibility of valley cloud, moderate wind from the southwest, treeline temperatures around -8 C.

Avalanche Summary

Over the weekend a few notable avalanches were reported including a snowmobile triggered avalanche near Silvern Lake that appeared to occur on a 30-50 cm deep surface hoar layer, and a few size 2-3 slab avalanches triggered by heavy machinery north of Hazelton that occurred on 30-70 cm deep layers (on northeast and southeast aspects around treeline). There were also reports of some large (size 2-3) naturally-triggered avalanches on wind-loaded slopes below cornices. Large avalanches with similar characteristics were observed on Friday, including one on Hudson Bay Mountain (see photos in this MIN report) and another one north of Starr Basin in the Telkwa Range.

Snowpack Summary

Wind and warm temperatures have created highly variable surface conditions. Open terrain is heavily wind-affected, surface crusts may extend into the alpine on south-facing slopes, and pockets of dry snow may still exist on northern aspects. Recent avalanche activity suggests there are two weak layers in the upper snowpack: one is a 30 cm deep surface hoar layer (buried on Jan 19) and the other is a 40 to 70 cm deep layer of faceted snow from the cold spell at the end of December. We are uncertain about the spatial distribution of these layers, but avalanche activity suggests they are most problematic in steep terrain at treeline and alpine elevations. In thin snowpack areas, the base of the snowpack is composed of weak faceted grains around various melt-freeze crusts, which are considered dormant at this time.

Terrain and Travel

  • Caution around convexities or sharp changes in terrain.
  • Be especially cautious as you transition into wind affected terrain.
  • Use ridges or ribs to avoid areas of wind loaded snow.
  • Avoid shallow, rocky areas where the snowpack transitions from thick to thin.

Problems

Persistent Slabs

An icon showing Persistent Slabs

A handful of large avalanches the past few days suggest buried weak layers in the top 70 cm of the snowpack could still produce avalanches. A noticeable trend is these avalanches have occurred in wind-affected terrain. Be careful with your terrain selection and be extra cautious around big slopes and steep convexities.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

1.5 - 2.5

Wind Slabs

An icon showing Wind Slabs

Watch for pockets of unstable snow in steep open terrain, especially along ridges.

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Valid until: Jan 25th, 2022 4:00PM