An afternoon tour in the Tincan Trees to suss out the snowfall from today and avalanche conditions.
Heavy snowfall (1-2″ per hour), moderate to strong winds from the North and East blowing snow at all elevations (even in the trees and near the road). Obscured skies.
Signs of instability:
Recent avalanches – Yes.
One small slab in a wind loaded zone was triggered intentionally by my partner on a steep roll in the trees. (10-14″ deep, 50′ wide running only 20-30′ – West facing 2,000′). Facets/surface hoar combo below storm snow and on top of late February crust was the weak layer. This slide showed clear ‘propagation propensity’ – meaning it propagated as wide as the slope would allow. This is a common characteristic of both facets or surface hoar as a weak layer.
Cracking – Yes.
Shooting cracks up to 20′ in length (see photo).
Snow surface obs:
6-8″ of new medium density snow at 2,500′ by 4pm and 6″ at the parking lot (snowfall really picked up about then however)
The 6-8″ of new snow (or rather 10-12″ at the time of writing, 7pm) is sitting on 1-2″ of weak faceted snow combined with surface hoar over a variable crust. The avalanche, as well as cracking observed, was failing at both this weak new/old snow interface or within the storm snow itself. The storm snow is a bit “upside-down”. This is likely due to the wind more than the temperature since the wind is getting to all elevations, including within the trees. Nonetheless, avalanche conditions were becoming very ripe by the late afternoon.
Due to the lack of visibility during a storm like this, there is little information on the goings-on above treeline. Yet, with the touchy-ness of the new snow in the trees today, one can suspect that natural avalanches were occurring and these will only become larger with additional snow and wind.