Human triggered avalanches remain possible, especially in wind loaded areas and at lower elevations where buried surface hoar layers exist.
Avalanche problems
Wind Slabs
N
NE
E
SE
S
SW
W
NW
Alpine
Treeline
Below treeline
Likelihood
Possible
Size
1–2
Previous variable wind directions have likely formed wind slabs on all aspects.
Persistent Slabs
N
NE
E
SE
S
SW
W
NW
Alpine
Treeline
Below treeline
Likelihood
Unlikely - Possible
Size
2–2.5
A weak layer of surface hoar is buried around 40 to 80 cm, and is most prominent between 1600 m and 1900 m.
Confidence
Moderate - Due to the number of field observations
Weather Forecast
THURSDAY NIGHT - Cloudy with scattered flurries, 5 cm / southwest winds 10-20 km/h / alpine low temperature near -15FRIDAY - Mainly cloudy with isolated flurries / southeast winds 10-20 km/h / alpine high temperature near -18SATURDAY - Mainly sunny / east winds 10-15 km/h / alpine high temperature near -25SUNDAY - Sunny / northeast winds, 10-20 km/h / alpine high temperature near -17
Avalanche Summary
On Monday, size 1 wind slabs were reactive to human traffic. One size 2.5 natural wind slab avalanche likely occurred overnight Monday.Several size 2 wind slab avalanches were triggered with explosives on Friday after a bout of strong to extreme southwest winds. Slab depths ranged from 20-60 cm.A MIN report from Grizzly Peak in the Elkford area last Thursday describes a persistent slab failing on the mid-January persistent weak layer as a group ascended a steep slope near treeline. See the report here.
Snowpack Summary
Up to 15 cm of new snow and previous variable wind directions will mean that wind slabs can be found on all aspects at upper elevations. Older wind slabs will be buried under the new snow and may be difficult to detect.A weak layer of facets (sugary snow) and surface hoar (feathery crystals) that was buried in mid January is down approximately 40-80 cm. This layer is most prominent between 1600 m and 1900 m, but it has been found up to 2200 m in some areas. This weak layer may exist in combination with a crust on south facing slopes. Recent snowpack tests and avalanche reports suggest that this layer remains reactive to human triggers.The bottom half of the snowpack is composed of weak, sugary facets.