Avalanche Forecast
Issued: Jan 18th, 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
A mix of heavy snowfall, strong wind, and a transition to rain are expected to maintain a widespread natural avalanche cycle in the region on Sunday. Travel in avalanche terrain is not recommended.
Summary
Confidence
Moderate - Forecast snowfall amounts are uncertain.
Weather Forecast
Saturday night: Cloudy with continuing snowfall bringing 30-40 cm of new snow. Moderate to strong south winds.
Sunday: Cloudy with easing snowfall bringing 10-15 cm of new snow before transitioning to light rain. Moderate to strong south winds. Alpine temperatures increasing to +3 as freezing levels climb to 2200 metres by afternoon.
Monday: Cloudy with wet flurries or rain bringing about 10 cm of new snow to the alpine. Moderate south winds easing over the day. Alpine temperatures around 0 to -1 with freezing levels to 1500 metres.
Tuesday: Cloudy with wet flurries bringing about 10 cm of new snow to alpine and treeline. Moderate south winds. Alpine temperatures around -2 with freezing levels dropping from 1400 metres to 1000 metres over the day.
Avalanche Summary
No avalanches from the current storm have yet been reported, but the ongoing storm has been forming a widespread new storm slab problem as new snow accumulates and forms slabs as a result of wind and rising temperatures. Active natural avalanche conditions are expected to have become increasingly widespread in areas that saw upwards of 25 cm of new snow by the end of the day Saturday.
A further rise in temperatures may allow for rain falling on snow late Sunday, which will further destabilize recent snow accumulations and promote wet loose avalanche activity.
Snowpack Summary
2-day snow totals over the region are expected to reach 50-60 cm by the end of the day on Sunday. The new snow has buried wind-affected surfaces in exposed areas at all elevations and soft, low density snow in sheltered areas.
The new snow will bring snow totals from the past week to about 170 cm. Collectively, all this snow rests on a hard melt hard melt-freeze crust below 1500 m and on previously wind-affected snow at higher elevations.
In some areas a weak layer of surface hoar exists above this crust. Recent snowpack tests on the North Shore have given variable, sometimes quite sudden results at this interface, particularly where this combination of crust and surface hoar was identified.
Terrain and Travel
- Storm slab size and sensitivity to triggering will likely increase through the day.
- Avoid all avalanche terrain during periods of heavy loading from new snow, wind, or rain.
Problems
Storm Slabs
Ongoing snowfall will continue to build storm slabs through Sunday. Strong winds and rising temperatures will aid slab formation and promote natural avalanche activity. Slabs are expected to become especially touchy as snowfall transitions to rain.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Loose Wet
Rising freezing levels and a transition from snowfall to rain are expected to add wet loose avalanches to the mix on Sunday. These are most likely to occur on steep slopes and may initiate naturally or with a human trigger.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Jan 19th, 2020 5:00PM
