Wind Slabs
- Alpine
- Treeline
- Below treeline
- Likelihood
- Possible - Likely
- Size
- 1–2
Winds have started to redistribute the recent storm snow with small slabs already developed. As winds increase Tuesday expect this process to accelerate.
Temperatures are on the rise.
A weak freeze is possible overnight Monday.
Increased winds Tuesday will encourage slab development.
Winds have started to redistribute the recent storm snow with small slabs already developed. As winds increase Tuesday expect this process to accelerate.
The Feb 3 crust/facet interface is down 70-110 cm. In shallow snowpack areas on northerly alpine aspects this layer remains sensitive to skiers, with remote triggering observed in several instances. All the recent avalanches that initiated on this layer stepped down to the basal facets / ground.
Warming temperatures should result in weak freezes overnight Monday. Solar inputs will likely be the main driver Tuesday with most activity on steep solar and rocky slopes but expect deterioration at lower elevations on shaded slopes as well.
Another slab was remote triggered from 50m today in the Purple Bowl at Lake Louise. The slab was reprorted to be 50cm deep and 75m wide. This would be a northwest aspect at around 2500m and would be skier's right of a similar event triggered on the February 3rd layer just over a week ago.
Otherwise a few loose wet events out of steep rocky terrain.
Up to 35 cm of snow over old sun crusts on solar aspects, with new solar crusts forming. On polar aspects, this snow sits over a layer of stellars/spotty surface hoar crystals and is worth monitoring.
Our main concern is shallow snowpack areas on northerly alpine aspects where no crusts are found in the upper snowpack and the midpack is thinner/weaker. Triggering the Feb 3 facet/crust layer and basal depth hoar remains possible.
Deeper snowpack areas have few concerns.
Upper level temperatures will increase through the night Monday as a warm system approaches. Some clouds develop with moderate westerly winds.
Tuesday temperatures will spike to around 5C at treeline and winds increase to strong SW. A cold front sweeps south bringing rain that will turn to snow overnight.
Wendnesday: Winds will fade as temperatures drop.
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