As freezing levels drop storm snow at higher elevations may remain reactive to human triggers. Watch for changing conditions as you gain elevation, and as you transition into wind affected terrain.
Cornices have grown large during the recent storms and may remain weak from warm temperatures. Falling cornices are hazardous and may trigger slabs avalanches on the slopes below.
Recent storm snow may remain reactive to human triggering. Expect greater reactivity and deeper deposits at higher elevations that were spared from rain, and on north through east facing slopes (from recent strong southwest winds).
Avalanches may involve the most recent snowfall (10-30 cm), or the settling storm snow from the past week (up to 70 cm) that sits over a widespread crust.
Temperatures remain cool over the weekend. Convective activity may bring short and localized bursts of snowfall.
FRIDAY NIGHT: Mostly cloudy with scattered flurries and moderate westerly winds. Freezing levels drop to near 500 m overnight.
SATURDAY: Mostly cloudy with flurries of up to 5 cm. Freezing levels around 1000 m. Moderate westerly winds.
SUNDAY: A mix of sun and cloud with scattered flurries possible. Freezing levels reach 1100 m. Light northeast winds.
MONDAY: A mix of sun and cloud. Freezing levels reach 1200 m. Light northeast winds.
On Thursday, several size 1.5 slab avalanches were triggered by skiers and riders. Natural wet avalanche activity was observed to size 1.5 on south facing slopes in many areas. Avalanches were observed up to size 3 in isolated features (where the snowpack sits over smooth rock slabs). Natural avalanche activity is expected to have continued overnight with rain, snow and wind. Avalanche activity is expected to decrease as freezing levels drop.
On Wednesday, natural wet avalanches were observed up to size 2.5 in steep terrain features. Several cornices falls have also been observed within the last 3 days.
On Tuesday, a skier remotely triggered two size 1 storm slabs on a northeast aspect at 2000 m in the north of the region. These were 30 cm thick and failed on the underlying melt-freeze crust.
At high elevations 10-30 cm of recent wind affected storm snow sits over moist snow, observed to around 2200m. Southwest winds have likely created deeper deposits on north and east facing slopes.
A widespread and supportive crust is buried 40-60 cm deep, below recent settling storm snow. This crust has been reactive to human and natural triggers within the last 5 days, but reports suggest it is beginning to bond.
Lower elevations hold wet snow from heavy rainfall, that will form a substantial crust as temperatures fall. The middle and lower snowpack are generally strong and well bonded.
