Avalanche Forecast
Issued: Feb 23rd, 2023 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs, Persistent Slabs and Deep Persistent Slabs.
PW,
Avalanche Canada
Winds will increase in strength through the day tomorrow, gusting to 80km/h in the alpine. Wind slabs will continue to pose a serious problem.
Summary
Confidence
Moderate
Avalanche Summary
The field team saw evidence of avalanches in the last 24h up to size 3. While the amount of activity is decreasing, natural and human triggering is still very possible.
One notable avalanche at Bow Summit ran onto the standard traverse track. See MIN.
Snowpack Summary
The recent storm snow continues to settle and feel the affects of the cold. Faceting of the upper snowpack was observed by the field team today as was extensive wind transport at ridge top elevations. Wind-slab's continue to develop at tree-line and into the alpine. These slabs have been formed primarily by north and east winds. These slabs are still reactive to human triggering. There are crusts in the middle of the snow pack and the base of the snowpack is still weak with basal facets. Test profiles done today are still producing sudden results in the basal facets.
Today's field team did a profile with a visiting forecasting team from Norway, which can be HERE.
Weather Summary
The next front will begin to move into the region tomorrow, slowly starting to warm temperatures up. Forecast highs in the alpine are between -15 and -20. As the front arrives, winds will shift to a southerly flow and increase in strength. Mainly clear skies tomorrow, with clouds developing in the afternoon. Friday night will be cold again before we break out of the cold snap on the weekend.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Make conservative terrain choices and avoid overhead hazard.
- If triggered, wind slabs avalanches may step down to deeper layers resulting in larger avalanches.
- Cornice failure may trigger large avalanches.
Problems
Wind Slabs
Up to 80 cm of storm snow in the past week, with strong north/east winds have created wind-slabs in alpine and tree-line locations. If triggered these wind-slabs may step down to the deeper weak layers and create larger avalanches.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Persistent Slabs
Slabs 80-120 cm deep overlie three persistent weak layers formed in January which are a mix of crusts on solar aspect, facets on northerly aspects and isolated surface hoar. These avalanches could also step down to the Nov facets and become even larger.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Deep Persistent Slabs
Facets and depth hoar at the bottom of the snowpack provide weak support for the entire snowpack. Incremental snowfall since the start of February has brought the overlying slab to the tipping point and we have started to see large, destructive avalanches failing on the November facets and running a long distance.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Feb 24th, 2023 4:00PM
