Avalanche Forecast
Issued: Mar 12th, 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.
trettie,
Avalanche Canada
Don't let relatively clear skies encourage you into big terrain features. The persistent weak layer continues to be a concern at alpine elevations, where wind slabs also exist.
Keep these problems in mind as you plan your travels.
Summary
Confidence
Moderate
Avalanche Summary
No new avalanches were reported on Saturday but observations are limited.
On Friday several recent size 2 wind slabs were observed in the Paddy Peak area. Observers noted active wind transport still occurring with snow available for transport.
On Tuesday, a size 2.5 persistent slab avalanche was remotely triggered by skiers on a ridgetop in the alpine. The slab propagated widely on a thin, rocky southeast aspect and it stepped down to basal facets lower on the slope.
Snowpack Summary
Moderate to strong winds from the north and northeast continue to scour exposed terrain, creating waves of sastrugi, and forming wind slabs on southerly aspects. Areas north of White Pass have more loose snow available for transport. Sheltered terrain in side valleys to the east and west of White Pass still may also hold softer snow for riding.
The middle of the snowpack is very firm and settled. There is a surface hoar layer buried from 60 cm (in Powder Valley, Tutshi, Paddy Peak) to 120 cm (White Pass) deep in sheltered, mostly north facing terrain features. On other aspects this layer exists as a crust and facets. Natural and human triggered avalanches have occurred on these layers recently and it remains a concern in alpine terrain.
At the base of the snowpack large sugary crystals persist.
Weather Summary
Sunday Night
Cloudy with trace amounts of new snow possible. Light northeast winds and a low of -19°C at 1500 m.
Monday
A mix of sun and cloud with the possibility of light flurries bringing trace amounts of new snow. Light to Moderate northeast winds and a high of -16°C at 1500 m.
Tuesday
A mix of sun and cloud with the possibility of light flurries bringing trace amounts of new snow. Light northeast winds and a high of -14°C at 1500 m.
Wednesday
Mostly cloudy with around 5 cm of new snow expected. Moderate southeast winds and a high of -10°C at 1500 m.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Be careful with wind slabs, especially in steep, unsupported and/or convex terrain features.
- If triggered, wind slabs avalanches may step down to deeper layers resulting in larger avalanches.
- Avoid steep, rocky, and wind effected areas where triggering slabs is more likely.
- Seek out sheltered terrain where new snow hasn't been wind-affected.
Problems
Wind Slabs
Wind slabs may remain reactive on west to south aspects in the alpine as winds continue to redistribute available snow. Hard wind slabs may be stubborn to human triggering, and initially feel supportive. Be aware of the potential for them to surprise you once you hit the weak spot.
Terrain around Powder Valley and Paddy Peak holds more snow available for transport than other areas. Fresh and reactive wind slabs are more likely to develop here.
Aspects: South East, South, South West, West.
Elevations: Alpine.
Likelihood
Expected Size
Persistent Slabs
A weak layer of surface hoar and/or a crust buried about 100 cm deep have produced large, widely propagating avalanches in the alpine last week.
Choose terrain conservatively with this layer in mind - avoid thin and rocky alpine start zones, sheltered north facing terrain features where surface hoar is most likely to be preserved and minimize your exposure to large open slopes where avalanches could propagate widely.
Aspects: All aspects.
Elevations: Alpine.
Likelihood
Expected Size
Valid until: Mar 13th, 2023 4:00PM
