Avalanche Forecast
Issued: Feb 13th, 2022 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Persistent Slabs.
wlewis,
Avalanche Canada
Avalanche danger is decreasing, but persistent layers are still possible to trigger. Continue to evaluate terrain as you travel.
Manage open slopes at treeline carefully, buried surface hoar is most likely to persist here.
Summary
Confidence
High - Uncertainty is due to the fact that persistent slabs are particularly difficult to forecast. We have a good understanding of the snowpack structure and confidence in the weather forecast
Weather Forecast
A cooling trend lowers freezing levels this week and a weak front brings light snowfall on Monday.
SUNDAY NIGHT: Freezing levels fall to 1000m. Light southerly winds with mostly cloudy skies. Chance of isolated flurries.Â
MONDAY: Mainly cloudy with light snowfall bringing up to 5cm over the day. Moderate southwesterly winds and freezing levels around 1500m. Alpine high of -2.Â
TUESDAY: Chance of flurries with moderate to strong nor'west winds. A mix of sun and cloud with freezing levels reaching 1500m. Alpine high -2.Â
WEDNESDAY: A mix of sun and cloudy with isolated flurries. Moderate nor'west winds, freezing levels reach 1500m, alpine high of -2.Â
Avalanche Summary
Last week, numerous persistent slab avalanches have been naturally and skier triggered - failing on the late January surface hoar and crust. These occurred on all aspects at treeline elevations and ranged from size 1 to size 3.
On Saturday, naturally triggered wet loose avalanches were observed to size 1 associated with the warming trend and sun.Â
Snowpack Summary
Exposed terrain at alpine and treeline elevations holds dense wind effected surfaces from westerly winds. Sheltered areas and lower elevations have a widespread melt freeze crust and surface hoar.
The late January interface is buried 20-40 cm deep, and consists of a melt-freeze crust at lower elevations and on solar aspects extending into the alpine. Surface hoar sits above the crust in sheltered areas at treeline and below. This layer is still producing human triggered avalanches and propagation-likely test results.Â
The mid January interface is buried 40-70 cm deep, and consists of a crust, facets, and surface hoar. The snowpack below is well consolidated, with the early December crust/facet persistent weak layer buried 100-200 cm deep. It is currently considered dormant. We expect this layer to become active later this season, check out the forecaster blog for more information.
Terrain and Travel
- Be aware of the potential for large avalanches due to the presence of buried weak layers.
- Look for signs of instability: whumphing, hollow sounds, shooting cracks, and recent avalanches.
- Be alert to conditions that change with aspect and elevation.
- Be careful as you transition into wind affected terrain.
Problems
Persistent Slabs
20-50 cm of settling snow sits over the January 30 surface hoar. Treat open slopes at and below treeline with extra caution where the surface hoar is most prominent.
The mid January crust/facet/surface hoar layer is down 40 to 120 and could be triggered in shallow snow pack areas or by a large load such as a cornice or step down avalanche.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Feb 14th, 2022 4:00PM
