Change is coming as a notable period of calm weather comes to an end.
Be aware of increasing winds on Tuesday: these winds are expected to increase natural avalanche activity in the region.
Forecasted winds on Tuesday will blow the 20-40 cm of loose dry snow on the surface and create sluffing and windslab conditions. We expect avalanche activity to increase as the winds increase throughout the day.
The surface snow will sluff easily in steep alpine terrain as the winds pick up on Tuesday.
In shallow snowpack areas (eg. windblown ridges or crossloaded slopes), weak facets and depth hoar associated with old crusts can be found near the base of the snowpack. Avoiding thin areas will help limit your exposure to this problem.
A field team on a flight with perfect visibility throughout Banff, Yoho and Kootenay observed a few natural size 2 windslabs in lee alpine terrain and a cornice failure that ran further than expected.
20-40 cm unconsolidated snow sits on the surface, waiting to be blown by incoming winds. The mid-pack is generally strong but a weak crust/facet layer can often be found near the ground, particularly in shallower areas. At treeline, average snowpack depths are 120-150 cm. The snowpack in Little Yoho is generally deeper and more consolidated than in areas further east in the BYK region.
The story of the next few days is wind. After a period of very calm conditions, the winds are forecasted to increase throughout the day on Tuesday. Expect strong to extreme ridgetop winds overnight on Tuesday and Wednesday. Temperatures will remain cold (-5 to -15 at treeline) and minimal to no snow accumulation by Friday.
