Avalanche Forecast
Issued: Feb 3rd, 2020 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Storm Slabs and Persistent Slabs.
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Avalanche Canada
Windy weather, with more snow expected, is keeping avalanche hazard elevated at treeline and alpine elevations. Minimize exposure to overhead wind-loaded slopes and cornices. The best riding is near treeline elevations in areas protected from the wind.
Summary
Confidence
Moderate - Forecast snowfall amounts are uncertain.
Weather Forecast
Sunday and Monday were the clearing between storms; the next storm expected to arrive Tuesday
Monday Overnight: Mix clouds and clear periods with temperatures in the minus teens. No new precipitation. Moderate west to southwest winds.
Tuesday: WINDY. Cloudy with very strong southwest or west winds . Snow with accumulations around 10 to 30 cm. Temperatures around -5 to -10 C.
Wednesday: Continued strong southwest or west winds. Continued snow with another 5 to 20 cm accumulating. Temperatures warming to near zero at 1500m.
Thursday: Cooling back to below zero temperatures with a northwest moderate wind. Dry with a mix of sun and clouds.
Avalanche Summary
Storm slab and wind slab avalanches reported from steeper slopes and slopes lee to southwest winds were reactive during and after the weekend storm. There's still snow avaiable to transport, as well as ongoing winds, so I expect wind slab activity may be ongoing.Â
Snowpack Summary
The Feb 01 weekend storm was warm and wet. Below a certain elevation, somewhere around 15 - 1700 m, the precipitation fell as a soaking rain which is now a frozen crust and avalanche concerns are minimal. Above this elevation there was 50 cm or more of recent snow, and strong winds creating both wind slab and cornice concerns.Â
In the mid-pack there may still be a layer of surface hoar buried in late December. It's gaining strength, but may remain a concern. The warm wet storm on Feb 01 will have tested this layer in the short-term and will improve it in the longer-term; however, we're awaiting evidence before considering it dormant. This layer is found across much of the North Rockies region but our focus is around McBride and the McGregors/Torpy.
Terrain and Travel
- Dial back your terrain choices if you are seeing more than 30 cm of new snow.
- Avoid exposure to overhead avalanche terrain, large avalanches may reach the end of run out zones.
- Expect slab conditions to change drastically as you move into wind exposed terrain.
- Back off if you encounter whumpfing, hollow sounds, or shooting cracks.
- Seek out wind sheltered terrain below treeline where you can avoid wind slabs and find great riding.
Problems
Storm Slabs
Strong winds continue to build Wind Slabs at higher elevations on northerly and easterly facing terrain features. Similarly CORNICES continue to grow, as does my concern of overhead hazard because of them. With Tuesday's incoming storm, where more than 30 cm of new snow accumulates slopes steeper than 35 degrees are subject to developing a storm slab avalanche problems
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Persistent Slabs
A weak layer of buried surface hoar may be found in parts of the region. There is uncertainty on where this layer is a problem, but it appears to be of highest concern in sheltered terrain features near treeline in the southern half of the region, particularly around McBride and the McGregors.
Aspects: All aspects.
Elevations: Treeline.
Likelihood
Expected Size
Valid until: Feb 5th, 2020 5:00PM
