Fresh snow arrives overnight with moderate wind. Find the best riding and safest avalanche conditions in wind-sheltered terrain. If you venture up into more exposed elevations, watch for reactivity in pockets of freshly wind-loaded snow.
Soft, fresh wind slabs may be found in unusual terrain features due to reverse loading by irregular wind direction. Wind slabs may sit over a sun crust on solar aspects and a rain crust below 2100 m. Crusts make a slick bed surface for avalanches.
An upslope system will bring enhanced snowfall to the eastern slopes of the Rockies Monday night. Greatest snowfall amounts will be near the Waterton border.
Monday night: Snowfall 15-20 cm on the eastern slopes of the range, 5-10 cm elsewhere. Light to moderate northeast ridgetop wind. Alpine temperature around -12 °C. Freezing level dropping to valley bottom.
Tuesday: Flurries bringing up to 5 cm. Light wind. Alpine high around -10 °C.
Wednesday: A mix of sun and cloud. Light wind. Alpine high around -15 °C.
Thursday: Mostly sunny. Strong northwest ridgetop wind easing to light. Alpine high around -7 °C.
On Sunday, explosive control work near Elkford produced cornice, storm slab and loose dry avalanches size 1.5-2.5 on north aspects in the alpine. Good visibility allowed observation of 2-3 day old storm slabs up to size 2.5 in the Castle backcountry. In neighboring Waterton National Park, ski cuts produced storm slabs and loose dry avalanches up to size 1.5.
On Friday and Saturday, avalanche activity was predominantly loose dry up to size 1.5.
10-25 cm of low density snow is forecast to fall by the end of the day Tuesday, favoring the eastern slopes of the range. The new snow arrives with some wind so watch for freshly loaded pockets of wind slab in leeward terrain features at upper elevations. It falls on a crust on steep south facing slopes and below 1500 m.
Last week's snowfall amounts varied widely through the region with as much as 50 cm in the south and as little as 10 cm in the north. Below 2100 m, a rain crust exists embedded within this snow. Below, a variety of old surfaces include a sun crust on solar aspects, and potentially weak, sugary crystals in shady areas.
The middle and lower snowpack are generally well consolidated, with a crust/facet layer from early December found near the ground. It is currently considered dormant but could become active later this season.
