Watch for windslabs in the alpine. The upper snowpack is slowly becoming more supportive and allowing for better travel, however, the lower snowpack remains weak and unsupported. Conservative terrain choices are still a good idea.
Strong to extreme winds on Sunday night formed small wind slabs in immediate lee areas of the alpine. These have been reactive to skier triggering in steep terrain.
The lower snowpack is comprised of weak facets and depth hoar with the upper snowpack forming a 40 to 90 cm thick slab above. This weak basal layer is uniform across most of the forecast region and has been responsible for most of the larger avalanche activity this season.
Sunshine ski hill reported some small skiier controlled avalanches in windloaded treeline terrain but otherwise no new avalanches observed or reported by sunshine, lake louise and Parks Canada forecasters in the Yoho Valley.
Recent moderate to strong winds have created windslabs in the alpine. Some suncrust exists on steep solar at treeline and below. Below this, the upper snowpack contains weak layers at 10-30 cm deep (Jan. 4th) and 25-50 cm deep (Dec. 17th) that are generally not reactive. The Nov 16 deep persistent layer is down 40-90 cm and continues to produce sudden failures in snowpack tests. In areas west of the divide, these layers are generally deeper and more spread apart in the snowpack.
A NW flow will bring windy conditions with broken skies and light flurries on Wednesday and Thursday. A cold front followed by an upslope and arctic air arrives on Friday.
Wed: Alpine winds strong from the NW. High temp ~ -4, low -12
Thurs: Alpine winds extreme from the NW. High temp ~ -4, low -8
Fri: 5-10 cm. Alpine winds light to moderate and switching to NW. Temps cooling to -15
