Use caution as you transition into wind exposed terrain, new snow combined with strong winds have promoted wind slab development at upper elevations.
25-45 cm of recent storm snow and strong west winds have formed wind slabs in many areas. These slabs will be the most reactive in wind loaded areas.
Weak snow at the bottom of the snowpack hasn't gone away. Evidence of deep persistent slab avalanches has been focused in the Sparwood-Elkford area over the past month. Human triggering is most likely around steep rocky terrain features, or anywhere the snowpack is thin and weak. Cornices have grown large and loom over many ridge lines, a failing cornice could initiate a deep persistent slab when it impacts the slope below.
WEDNESDAY NIGHT- Clear periods / northwest wind, 20-30 km/h / alpine low temperature near -12
THURSDAY- A mix of sun and cloud / west wind, 10-30 km/h / alpine high temperature near -10
FRIDAY- Mainly cloudy with flurries, 5-10 cm / northeast wind, 20-50 km/h / alpine high temperature near -16
SATURDAY- Mainly cloudy with flurries, 5 cm / northeast wind, 30-60 km/h / alpine high temperature near -23
Wind slabs at upper elevations may be reactive to human triggers. Cornices have also grown large with the recent weather pattern and a cornice failure could trigger a wind slab avalanche on the slope below.
In the neighbouring Waterton Lakes National Park region, there were several natural loose dry avalanches up to size 1.5 reported on Monday.
In the neighbouring Lizard Range on Sunday, loose dry and soft slab avalanches were sensitive to human triggering and explosive avalanche control work to size 1.5. These avalanches were 10 to 20 cm in depth, running fast and far.
5-15 cm of snow on Tuesday night brought total recent storm snow totals to 25-45 cm. Strong winds are promoting continued wind slab development. The new snow sits on wind slabs in exposed areas, and a sun crust on solar aspects (south through west facing slopes). Melt-freeze crusts extend up to about 1900 m on other aspects.
A thick crust with facets on it currently sits 40-80 cm below the surface and can be found up to 2100 m. The middle of the snowpack is generally strong, but the base of the snowpack contains basal facets that are most prominent in shallow rocky start zones.
