Avalanche Forecast
Issued: Feb 10th, 2023 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs and Persistent Slabs.
dsaly,
Avalanche Canada
Fresh flurries and recent snow are being impacted by the wind. Be most suspicious of deeper, loaded pockets around sharp changes in terrain.
Summary
Confidence
Moderate
Avalanche Summary
With the field team back in White Pass we received preliminary observations on Friday of thin, wind slabs reactive to riders and failing naturally with increasing wind from the southwest.
As we track a persistent layer deeper in the snowpack, the most recent reports are now over a week old when a couple of large (size 2-3) persistent slab, human-triggered and natural avalanches occurred near ridgetops in north-to-northeast alpine terrain. These avalanches showed an impressive capability to propagate across large distances. Here is a link to the most recent human-triggered size 3 avalanche.
If you are out in the backcountry please share your observations with the Mountain Information Network!
Snowpack Summary
The wind has impacted 30-40 cm recent snow, this pressed snow covers a crust up to 1700 m and wind-pressed surfaces at higher elevations.
Our field team continues to track a persistent layer of surface hoar and/or facets 50-100 cm deep, found on north and east aspects at upper treeline areas and higher. This layer has not produced any recent avalanches in the region and producing more stubborn results or non-results in snowpack recently.
Weather Summary
Friday night
Overnight flurries, 5-10 cm by Saturday morning. South-southwest wind gusting to 60 km/hr. Treeline low temperature -16 C.
Saturday
Flurries through the day, 5-15 cm accumulation by 4 pm. Strong southwest wind 40-60 km/hr. Treeline high temperature -7 C.
SundayFlurries starting late Saturday, 5-10 cm through Sunday afternonn. South wind 30-50 km/hr. Treeline high temperature -6 C.
MondayMostly cloudy with isolated flurries, 5 cm through the day. Southwest wind easing to light. Treeline high temperature -8 C.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Pay attention to the wind, once it starts to blow fresh sensitive wind slabs are likely to form.
- Carefully assess open slopes and convex rolls where buried surface hoar may be preserved.
- Persistent slabs have potential to pull back to lower angle terrain.
Problems
Wind Slabs
10 cm fresh snow Friday morning was quickly impacted by southwest wind. More snow overnight and into Saturday on the way is forecast to fall with steady southwest winds. Be most suspicious of deeper, loaded pockets around sharp changes in terrain. Expect to find a more widespread slab problem in areas with over 25 cm fresh snow.
Aspects: North, North East, East, South East, South, North West.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Persistent Slabs
Buried weak layers produced large, surprising avalanches last week. These layers are on a strengthening trend, but they may still be triggerable where the snowpack is thin. Avalanche activity associated with this problem was observed on north to northeast alpine terrain on preserved surface hoar that is now buried about 100 cm deep. Keep in mind that large avalanches can run far into flatter terrain and that stiff slabs can also pull back into flatter terrain above them.
Aspects: North, North East, East, South East, West, North West.
Elevations: Alpine.
Likelihood
Expected Size
Valid until: Feb 11th, 2023 4:00PM
