New snow, warm temperatures and extreme winds will create dangerous avalanche conditions on Monday.
Watch for conditions changing as snow accumulates throughout the day. Continually assess the bond of new snow to old surfaces as you move through the terrain.
Extreme southwest winds and new snow will form fresh reactive storm slabs on Monday. Be particularly cautious of lees at alpine and treeline. Slabs may be particularly reactive on solar slopes where they are poorly bonded to the underlying crust.
Where rain is saturating the snowpack below the treeline watch for signs that the upper snowpack is losing cohesion. Avoid steep terrain where wet heavy snow is more likely to release.
On Friday, fresh wind slab formation was observed as moderate to strong northeast wind redistributed the surface snow into immediate lees, as seen in this MIN report from the Fernie area.
On Saturday, several small natural loose dry and storm slab avalanches were observed in steep alpine features.
Accumulating flurries on Monday will cover a variety of surfaces including small pockets of wind slab on exposed south and west slopes, hard wind-affected surfaces in open areas, a sun crust on steep solar aspects, and facetted snow in sheltered areas.
The mid-snowpack is generally well-settled. 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.
Sunday Night
Mainly cloudy with isolated flurries, 2-3 cm accumulation. Alpine temperatures reach a high of -2 °C. Ridge wind 40 km/h from the southwest. Freezing levels remain at 1300 meters.
Monday
Cloudy with mixed precipitation, 5-9 cm of new snow accumulation at upper elevations. Alpine temperatures reach a high of 0 °C. Ridge wind 40-60 km/h from the southwest. Freezing levels rise to 1800 meters.
Overnight, flurries intensify bringing 15-25 cm of snow to higher elevations.
Tuesday
A mix of sun and cloud with isolated flurries, 1-2 cm accumulation. Alpine temperatures drop to a low of -5 °C. Ridge wind eases from 40 to 20 km/h from the southwest. Freezing level 1300 meters.
Wednesday
A mix of sun and cloud. Alpine temperatures reach a high of -3 °C. Ridge wind 10-25 km/h from the southwest. Freezing level 1500 meters.
More details can be found in the Mountain Weather Forecast.
