Monday January 13, 2020
Persistent Slab, Wind Slab
Travel & Terrain Advice
Choose low-angled and sheltered terrain, continuing to remain vigilant of newly formed wind slab especially on southern aspects.
Careful snow pack assessment and selective route finding is essential when entering any convex roll or steep features.
Past 72 hours, ski cutting on all aspects at treeline produced mostly size 1 wind slabs down up to 20 cm. No other avalanches observed or reported.
Found at Alpine and on all aspects, expect this avalanche problem to be stubborn to light triggers such as skiers. The chance of these avalanches being triggered is unlikely but if triggered may produce avalanches that are large to very large, greater than size two.
Found at all elevations and on all aspects, and especially on southern aspects as the strong outflow north wind will have refreshed slopes. Expect this avalanche problem to be stubborn to touchy to light triggers such as skiers. The chance of these avalanches being triggered is possible to likely and when triggered may produce avalanches size two or greater.
Over the past 24 hours, cool temperatures and light snowfall has refreshed the upper snow pack. Previous warm and wet storm fronts have formed a number of melt freeze crusts that are dominating the upper snow pack. The strength and support of these melt freeze crusts is dependent on elevation and are currently strong enough to bridge the mid and lower snow pack . A surface hoar layer down 30 to 40 cm is reactive to hard testing but in specific Alpine terrain is likely to be increasingly sensitive and may be problematic. The lower snow pack is well settled but in isolated Alpine terrain, suspect a deep and dormant basal weakness to exist.
|Surface||New low density snow, scoured loaded and pressed, all dependent on the orientation to the wind,|
|Upper||A breakable rain crust can be found down between 10 to 20 cm and on lee aspects upto 50cm.|
|Mid||A variety of crusts from melt freeze to a settling surface hoar interface.|
|Lower||Well settled and dense, with the exception of the alpine where a deep an nonreactive basal instability is possibly still lurking.|
A series of past warm pacific storm fronts in the region delivered fluctuating freezing levels and precipitation in the form of rain and snow.
An arctic front will bring some unsettled weather but frigid temperatures will persist, expect the treeline and alpine temperatures to cool to the negative mid teens. A mix of sun and cloud with a dry air mass will continue into Tuesday and Wednesday.
Monday Nil precipitation , Winds Light from the North east , Freezing levels sea level.
Tuesday 1 to 5 mm of precipitation , Winds light from the North east, Freezing level sea level.
Wednesday 1 to 5 mm of precipitation , Winds light from the North east, Freezing level sea level.
Posted on Monday January 13, 2020 by Jesse Percival