Avalanche Forecast
Issued: Feb 21st, 2021 8:09AM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Storm Slabs, Loose Dry and Persistent Slabs.
Kate Ryan,
Avalanche danger may reach EXTREME in the overnight period with forecast extreme winds and ongoing snowfall.
Avoid exposure to avalanche terrain today and tomorrow.
Summary
Weather Forecast
Zonal flow sets up over BC today, bringing moderate to heavy snow and strong to extreme southwesterly winds to Glacier Park.
Today: 10cm snow. Winds SW 35-55km/h gusting to >100km/h. Freezing level 1400m.
Tonight: 17cm snow. Winds SW 35 gusting to 100km/h. Freezing level 1200m.
Monday: 9cm. Winds W 25 gusting to 65km/h. Freezing level 1400m.
Snowpack Summary
Strong south winds and up to 10cm of snow overnight. The Feb 14 drought interface is now down 30-50cm in sheltered areas; this interface is predominantly a wind crust in exposed areas near the height of the pass, and buried windslabs and facets as you move East and West. Facets, and a weak suncrust still linger down ~80cm at the Jan. 24th PWL.
Avalanche Summary
Large natural avalanches started occurring yesterday afternoon and continue today, from steep, alpine features. Skier triggering of small slab avalanches was also observed yesterday from steep lee features at treeline.
Confidence
Problems
Storm Slabs
40cm of storm snow and counting is being redistributed by strong S'ly winds. This lies over the Valentine's Day weak interface of facets, crusts and variable wind effect. Expect slab properties to increase throughout the day as the storm intensifies.
- The recent snow is now hiding windslabs that were easily visible before the snow fell.
- Avoid exposure to avalanche terrain, large avalanches may reach the end of run out zones.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Loose Dry
Expect the new snow to be easily triggered in steep terrain below treeline that is sheltered from the wind. Loose snow avalanches will gain mass quickly where the new snow sits on previously faceted and unconsolidated snow.
- Use caution above cliffs and terrain traps where small avalanches may have severe consequences.
Aspects: All aspects.
Elevations: Below Treeline.
Likelihood
Expected Size
Persistent Slabs
The Jan 24th interface has been found in numerous recent profiles. This layer may wake-up with increased load from the storm! It is most concerning on steep, unsupported terrain features on solar aspects, where it exists as a sun crust.
- Persistent slabs may be more sensitive to human triggering on solar asp where it sits on sun crust
Aspects: South East, South, South West, West.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Feb 22nd, 2021 8:00AM
