Avalanche Forecast

Moderate - Track of incoming weather systems is uncertain on Saturday

The south of this region will see significantly more snow from the storm on Saturday (15-20cm possible). Clearing and becoming cold on Sunday as frigid arctic air moves inSATURDAY: Snow (15-20 cm possible in the far south with 5-10cm more likely near Golden). Tree line temperature around -12C. Winds southwesterly 30km/h.SUNDAY: Clearing, but lingering flurries possible. Tree line temperatures around -20C. Winds light northeasterly.MONDAY: Sunny but cold. Alpine temperatures near -18 Celsius. Winds light northerly.

On Friday, skiers were able to intentionally trigger small (size 1) wind slab avalanches in immediate down wind (lee) features near ridge crests. See here for an update on conditions near Golden. On Wednesday, a few small avalanches, including one involving a skier, were reported in recent storm snow with crowns approximately 30 cm deep.A week ago, explosive control work continued to produce large, deep avalanches up to size 3 on north to southeast aspects above 2200m. On the same day, a skier is believed to have remotely (from a distance) triggered a size 1.5 avalanche on a northwest aspect at 2800m that failed on the early January layer.Although deeper, persistent avalanche activity is becoming less frequent, these avalanches point to the continued reactivity and destructive potential of these layers.

Recent storm snow totals are 10-20cm. I suspect moderate south west through north west winds shifted these accumulations into deeper, reactive slabs in wind-exposed terrain. These accumulations overlie a mix of older wind slabs in exposed higher elevation terrain, a sun crust on steep solar aspects and surface hoar on sheltered slopes.Below the snow surface several persistent weak layers make up a troublesome snowpack which is not tolerating recent storm loads. In the top 1-2 m of the snowpack, two surface hoar/ crust layers buried in January can be found. Expect to find one or other of these on all aspects and elevations.Deeper in the snowpack (around 200 cm deep) is a facet/crust/surface hoar layer from December, most prevalent at and below treeline.Near the base of the snowpack is a crust/facet combo, most likely to be triggered from thin spots in the alpine.All of these layers have produced large avalanches recently. The wide distribution and ongoing reactivity of these layers suggests that avoidance through choosing simple terrain is the best strategy.