Avalanche Forecast
Issued: Jan 19th, 2020 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Storm Slabs and Loose Wet.
cgarritty,
Avalanche Canada
Make observations of surface conditions to determine whether you need to manage loose wet or storm slab avalanche hazards on Monday. Conditions will vary with elevation.
Summary
Confidence
Moderate - Uncertainty is due to rapidly fluctuating freezing levels.
Weather Forecast
Sunday night: Cloudy with light rain. Moderate to strong south winds. Freezing levels beginning to drop from 2300 metres around midnight.
Monday: Cloudy with wet flurries or rain bringing 5-20 cm of new snow, increasing with elevation from treeline to the alpine, rain below about 1300 metres. Moderate south winds easing over the day. Alpine temperatures around 0 to -1 with freezing levels to 1500 metres.
Tuesday: Cloudy with flurries bringing 10-25 cm of new snow, increasing with elevation. Moderate to strong south winds. Alpine temperatures around -3 with freezing levels around 1200 metres.
Wednesday: Cloudy with isolated flurries and a trace of new snow, increasing and becoming rain overnight. Light southeast winds. Alpine high temperatures around -2, rising overnight.
Avalanche Summary
Observations from the weekend storm are still limited, but initial reports from Saturday described new slabs reacting to ski cuts on steeper features up to treeline on the North Shore. Fracture depths of up to 20 cm were observed.
Looking forward, continuing snowfall is expected to maintain similar conditions on Monday, with new snow and associated avalanche hazards increasing with elevation.
Snowpack Summary
5-20 cm of new snow, increasing with elevation, is expected to fall in the region by the end of the day Monday. This will cover wet surfaces at all elevations as a result of rain over Sunday night.
The weekend storm brought an elevation-dependent 5 to possibly 50 cm of new snow to the region, with the greatest amounts confined to the high alpine. The new snow buried wind-affected surfaces in exposed areas at all elevations and soft, low density snow in sheltered areas.
The new snow brought snow totals from the past week to about 100-170 cm, again increasing with elevation. This snow is expected to have now formed a strong bond with the hard melt hard melt-freeze crust present below 1500 m.
Terrain and Travel
- Storm snow and wind is forming touchy slabs. Use caution in lee areas in the alpine and treeline.
- Watch for unstable snow on specific terrain features, especially when the snow is moist or wet.
- Remember that the snowpack will be significantly different at higher elevations than lower down.
Problems
Storm Slabs
Fresh storm slabs are expected to build on Monday, with depth and reactivity that increases with elevation and exposure to wind. Switch your mindset to managing wet loose avalanches if you find rain accumulating at treeline instead of new snow.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Loose Wet
Wet loose avalanche conditions should ease as temperatures drop on Monday, but surface snow will remain unstable at elevations that continue to see rain accumulating instead of new snow. Be conscious of this problem around steep slopes at lower elevations.
Aspects: All aspects.
Elevations: Treeline, Below Treeline.
Likelihood
Expected Size
Valid until: Jan 20th, 2020 5:00PM
