Avalanche Forecast
Issued: Feb 27th, 2022 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs and Persistent Slabs.
jleblanc,
Avalanche Canada
Recent snowfall amounts vary significantly within the region. If you are recreating near Blue River, Albreda or Valemount, make sure to also read the North Columbias avalanche forecast.
Summary
Confidence
Weather Forecast
A series of storms are set to be impacting the region in the next few days. Light to moderate snowfalls, rising freezing levels, and warmers temperatures are expected until mid-week.
Sunday night: Flurries up to 5 cm. Freezing level returning to valley bottom. Alpine temperatures around -8 C. Moderate southerly winds.
Monday: Flurries. Freezing level rising to 1400 m. Alpine temperatures around -4 C. Moderate southerly winds, increasing all day to 50 km/h.
Tuesday: Snow 10-15 cm. Freezing level rising to 1600 m. Alpine temperatures around -2 C. Moderate southerly winds gusting 50 km/h.
Wednesday: Snow 5-10 cm. Freezing level rising to 1400 m. Alpine temperatures around -4 C. Moderate southerly winds.
Avalanche Summary
Saturday, a small natural wind slab avalanche was triggered by cornice fall near Valemount on a steep alpine slope. Another cornice triggered a very large (size 3) persistent slab avalanche in the same area on a south-facing slope Friday.
It highlights the fact that wind slabs and persistent slabs remain a concern in this region, although a large load is required to initiate a persistent avalanche.
Snowpack Summary
About 10-20 cm of fresh snow has fallen Sunday throughout the region, with favoured amounts near Blue River and Albreda. This new snow is now covering a wide variety of surfaces, including heavily wind-affected surfaces on most alpine slopes, fresh wind slabs on any open features, thin sun crust on steep south-facing slopes at all elevations, and widespread large feathery surface hoar crystal on sheltered areas. Below ~1200 m, 25-35 cm of snow is now overlying a thick melt-freeze crust.
Two weak layers exist within the upper snowpack: the mid-February layer (down 60 to 110 cm) and the mid-January layer (down 90 cm). They both consist of surface hoar / melt-freeze crust. Although reactivity of these layers had tapered off lately, they should be treated with extra caution with this incoming series of snowfalls as they may produce large, unexpected avalanches.
Terrain and Travel
- Wind slabs are most reactive during their formation.
- Back off if you encounter whumpfing, hollow sounds, or shooting cracks.
- Closely monitor how the new snow is bonding to the old surface.
- If triggered, wind slabs avalanches may step down to deeper layers resulting in larger avalanches.
Problems
Wind Slabs
Strong winds likely redistribute fresh new snow (10-20 cm) and build reactive wind slabs on any exposed terrain, lee features, and around ridgelines. Use increased caution around treeline or alpine features where these slabs may overlay a weak layer, sun crust or hard wind slabs.
Aspects: North, North East, East, North West.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Persistent Slabs
Two weak layers exist within the upper snowpack: the mid-February layer (down 70 to 120 cm) and the mid-January layer (down 100 cm). They both consist of surface hoar / melt-freeze crust. With warmer temperatures and increase, they have the potential to "wake up" and produce large, unexpected avalanches. In times of uncertainty, choose simple terrain, low consequence slopes and conservative lines.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Feb 28th, 2022 4:00PM
