Avalanche Forecast
Issued: Feb 6th, 2023 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Storm Slabs and Loose Wet.
rgoddard,
Avalanche Canada
Major storm system brings major precipitation and increased avalanche hazard.
Expect storm slabs that will be made even more reactive with strong winds and be cautious of loose wet avalanches at lower elevations.
Summary
Confidence
Avalanche Summary
A large storm slab avalanche was reported in the Tetrahedron yesterday. We anticipate more of these types of avalanches with incoming weather. Widespread natural storm slabs and loose wet avalanche activity during periods of heavy snowfall/rain Monday and Tuesday will ramp up avalanche activity. There is potential for deep storm slabs to slide on a buried crust, producing large and destructive avalanches.
Please continue to post your reports and photos to the Mountain Information Network, the information is very helpful to forecasters.
Snowpack Summary
By Tuesday morning there could be 60 to 70 cm of new snow at elevations of about 1000 m. At upper elevations, the new snow adds to 40 cm of recent snow sitting over a hard crust. This will be accompanied by strong winds and warm temperatures so expect wind slabs in exposed areas. Snowpack tests have shown a poor bond between the crust and overlying snow. The middle and lower snowpack is strong and bonded.
Weather Summary
Monday Night
Cloudy, 40 to 50 cm accumulation with a mix of snow and rain below 1500 m easing throughout, wind south southwest 50 km/h, treeline temperatures -1 C.
Tuesday
Cloudy, 25 cm accumulation with a mix of rain below 1400 m, wind southwest 40 to 50 km/h, treeline temperatures -1 C.
Wednesday
Mainly cloudy, trace accumulation, wind northwest 10 to 20 km/h, treeline temperatures -5 C.
Thursday
Cloudy, 5 to 8 cm accumulation at higher elevations, wind southeast 20 km/h gusting to 50, treeline temperatures at -5 C.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Storm slab size and sensitivity to triggering will likely increase through the day.
- Good day to make conservative terrain choices.
- Keep in mind the crust offers an excellent bed surface for avalanches.
- As surface loses cohesion due to melting, loose wet avalanches become common in steeper terrain.
- Choose low-angled, sheltered terrain where new snow hasn't been wind-affected.
Problems
Storm Slabs
A storm system that arrives Monday and will continue to bring snow on Tuesday will increase the chance of storm slab avalanches. Below around 1600 m this snow may be rain and it too will add load to the snow pack. Strong southerly winds that accompany this weather system will load pockets of areas with even more accumulation.
Storm slabs may slide easily on an underlying crust. Be especially cautious where winds have redistributed new snow into deep pockets in lees, watch for an increase in slab properties and reactivity.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Loose Wet
A rain saturates the upper snowpack at lower elevations, loose wet avalanches will become increasingly likely.
Aspects: All aspects.
Elevations: Below Treeline.
Likelihood
Expected Size
Valid until: Feb 7th, 2023 4:00PM
