Avalanche Forecast
Issued: Feb 27th, 2023 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Storm Slabs.
wlewis,
Avalanche Canada
Storm snow keeps stacking up and may take days to bond with the old wind affected surface.
Watch for increased reactivity in wind loaded terrain, and manage your sluff in steep features.
Summary
Confidence
Avalanche Summary
As the storm progressed on Sunday, storm slab avalanches were reported to size 2 from natural and rider triggers, and explosive control methods. The storm snow was reported to be very reactive, with wide propagation where terrain allowed.
Most avalanches have occurred within the storm snow or on the old snow surface, while a few failed on the buried surface hoar layer.
Snowpack Summary
Around 40 cm of low density recent storm snow sits over heavily wind affected surfaces at all elevations. Expect deeper deposits on north and east facing slopes, from southwest winds. In steep and sheltered terrain the low density snow has minimal slab quality.
A layer of surface hoar can be found on shaded slopes, and a sun crust on sun affected slopes buried 30-60 cm deep. Otherwise, the snowpack is generally well consolidated and bonding.
The lower snowpack includes a layer of weak sugary crystals near the ground. These facets are slowly gaining strength and have not produced recent avalanche activity. We continue to track the layer and watch for any signs that it could wake up and produce very large avalanches.
Weather Summary
Monday Night
Mostly cloudy with flurries, up to 5-10 cm of snowfall favors the south. Light southerly winds. Freezing levels at valley bottom.
Tuesday
Cloudy with light snowfall, 2-5 cm in most areas. Terrain near the USA border may see up to 10 cm. Light southerly winds. Freezing levels at valley bottom, alpine high of -5 °C.
Wednesday
Mostly sunny with some cloud. Moderate westerly winds. Alpine high of -3 °C. Freezing levels reach 1000 m. No snowfall expected
Thursday
Cloudy with light snowfall delivering around 5 cm overnight, and 10 cm over the day. Moderate to strong southwest winds. Freezing levels reach 800 m, with an alpine high of -5.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Continue to make conservative terrain choices while the storm snow settles and stabilizes.
- Be aware of the potential for larger than expected storm slabs due to the presence of buried surface hoar.
- Don't be too cavalier with decision making, storm slabs may remain sensitive to human triggering.
Problems
Storm Slabs
Storm snow is expected to remain reactive to human triggers. It sits over dense wind affected surfaces and is taking some time to gain strength and bond. Greater slab quality and propagation has been seen in wind affected terrain, while in sheltered areas storm snow is reacting as loose dry sluffing.
A layer of buried surface hoar may increase reactivity and produce larger avalanches than you expect - this is more likely to be found in sheltered and shaded terrain features. Reports suggest this is most prominent in the northern areas of the region.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Feb 28th, 2023 4:00PM
