Thursday February 14, 2019
Wind Slab, Loose Dry
Travel & Terrain Advice
Winds are expected to pick up again on Thursday and this may result in some snow transport. Be aware of lee features at higher elevation bands where snow has remained cold, light and dry. Avalanches up to size 2 could possibly be initiated on terrain below ridges, in depressions and at mountaintop below cornices. Keep your eyes peeled for cornice development on West and North Westerly aspects including mountain top and ridges. Beware of snow cracking underfoot or under your snowmobile and take this as a clear indication of unstable snow. If you are travelling at higher elevation bands, cautious route finding and careful decision making and terrain selection will make for a successful outing.
Despite the recent precipitation and winds in recent days the snowpack is well settled. Signs of natural and human triggered avalanches had occurred as recently as this past weekend at Mt cain (3 x human triggered size 1-2) and early Monday at Mt Adrian snowmobile area (size 1 natural) however now that precipitation and winds have slowed the snowpack is gaining consolidation. Although the snowpack is well bonded, sloughing remains a concern on steep unsupported terrain in the size 1 range as well.
Moderate to strong snow transport begins Thursday February 14th. The approximate 30-60 cm of dry powder snow potentially available for transport could be redistributed by Thursdays winds and form winds slabs on leeward terrain on Northerly and North Westerly Aspects. We could expect possible triggering of avalanches (up to size 2) on terrain below ridges, in depressions and on leeward terrain at mountaintop and ridgetop.
Loose dry ‘sloughs’ could pose a threat to recreational users travelling on steep unsupported terrain. There is currently 30-60 cm of unconsolidated snow that sits atop a firm melt freeze crust. There remains a possibility of triggering ‘sloughing’ and size 1 avalanches as a result of this unconsolidated snow on steep unsupported terrain.
The snowpack is very well settled with 30-60cm of light dry powder snow at the surface of the snowpack. Below is an extremely well consolidated snowpack. Generally speaking, the primary concern lies in loose dry avalanches that can be initiated on steep unsupported terrain and leeward slopes that might show signs of wind slab, such as dense “upside down” snow and/or cracking underfoot.
|Surface||30-60cm of light dry powder snow|
|Upper||light dry snow and below an extremely stiff and nearly "unbreakable" melt freeze crust|
|Mid||Well bonded midpack that does include two weaker "dormant" layers (Facet layer and Surface Hoar layer)|
The cold temperatures showed signs of weakening and warming today February 13th, one Treeline weather station showed a maximum day time high of nearly 0 degrees celsius. Evenings temperatures continue to drop well below zero into the double digits, including Wednesday February 13th.
Thursday: 4 to 6 cm of new snow, Temperature -1 to -9 degrees, Moderate to Strong Winds from the East South East , Freezing Level 650M
Friday: 1 to 6 cm of new snow, Temperature +1 to -5 degrees, Moderate to Light Winds from the South, Freezing Level 1,000M
Saturday: 1 to 7 cm of new snow, Temperature 0 to -11, Light Winds shifting from the South to the North, Freezing Level 600M
Posted on Thursday February 14, 2019 by Ryan Shelly