Avalanche Forecast
Issued: Mar 3rd, 2021 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs, Cornices and Loose Wet.
astclair,
Avalanche Canada
Check steep or confined lines for wind slab or wet surface snow before committing and give cornices a wide berth from above and below.
Summary
Confidence
Weather Forecast
Wednesday night: Mostly cloudy, strong south wind above 2000 m, freezing level dropping to 1000 m.
Thursday: Increasing cloud, scattered flurries with up to 5 cm of snow beginning in the afternoon, strong south wind, freezing level rising to 1600 m.
Friday: Overcast, 30-40 cm of new snow, strong south wind with extreme gusts, freezing level near 1300 m.
Saturday: Mostly cloudy, 5-10 cm of snow, light southwest wind, freezing level near 1000 m.
Avalanche Summary
Large cornices (size 2) continue to be reactive to explosives. Explosive mitigation since Monday has also triggered a small (size 1) loose dry and storm slab avalanche. Minor pinwheeling has been observed on steep solar aspects in the afternoon.
Snowpack Summary
A slight rise in temperature and 5-10 mm of precipitation beginning in the afternoon on Thursday may increase the potential for wet loose avalanche activity on slopes experiencing warming for the first time. Watch for pinwheels and roller balls, as they are a clear indication of this problem. You can avoid them by staying off steep slopes when the snow becomes wet or slushy.
Strong winds from the south at upper elevations have formed shallow wind slabs in lee terrain features that may be possible to trigger. Recent winds have varied in direction, so watch for wind slabs on a variety of aspects.
In sheltered areas, 20 cm of recent snow sits over a layer that may consist of of facets, spotty surface hoar, and/or crusts on steep solar aspects and below 1500 m. A weak layer buried in mid-February is composed of a crust, facets or spotty surface hoar depending on elevation/aspect, and is now down 50-80 cm. There have been no recent avalanches reported on this layer. Large triggers, such as an avalanche in motion, cornice fall, or intense loading from snow, wind and/or a rapid rise in temperature could awaken these deeper weak layers.
The mid and lower snowpack is well settled and strong in most areas.
Terrain and Travel
- Recent wind has varied in direction so watch for wind slabs on all aspects.
- Carefully evaluate steep lines for wind slabs.
- Pay attention to cornices and give them a wide berth when traveling on or below ridges.
- Extra caution for areas experiencing rapidly warming temperatures for the first time.
Problems
Wind Slabs
A modest supply of new snow has fueled the continued formation of thin but potentially reactive wind slabs. Older wind slabs exist on a variety of aspects and may remain reactive where they sit over facets.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Cornices
Cornices are large and looming, and they require extra caution under the current conditions.
Aspects: North, North East, East, South East, South, North West.
Elevations: Alpine.
Likelihood
Expected Size
Loose Wet
Loose wet avalanches are most likely on slopes experiencing above freezing temperatures for the first time. A wet snow surface, pinwheeling, or point releases from rocks are good indicators that it is time to back off.
Aspects: All aspects.
Elevations: Treeline, Below Treeline.
Likelihood
Expected Size
Valid until: Mar 4th, 2021 4:00PM
