Explosives trigger destructive avalanche on Park City ridgeline as UAC issues highest-level warning

Wednesday's snow storm has created dangerous avalanche conditions throughout Utah. Photo: Utah Avalanche Center

Avoid all avalanche terrain. Stay off of and out from under slopes steeper than 30°. Carry and know how to use avalanche rescue equipment. Find safer riding conditions on slopes less than 30° with no overhead hazard

PARK CITY, Utah — The Utah Avalanche Center upgraded its avalanche watch to a warning Wednesday. This is the most severe alert level available, citing unusually dangerous conditions across the Wasatch Range.

The UAC reports that mitigation teams on the PC Ridgeline triggered a D2.5 avalanche, large enough to damage a vehicle, using explosives. The slide ran 300 feet wide, releasing as a wind slab into weak, old snow on a north aspect at 9,100 feet.

Avalanche danger is forecast to rise to HIGH on mid- and upper-elevation slopes facing E-N-NW through the day. Avalanches can be triggered more than three feet deep on a buried persistent weak layer, can break hundreds of feet wide and can release remotely. The UAC recommends avoiding all avalanche terrain, staying on slopes below 30 degrees and remaining well clear of anything connected to steeper terrain.

Storms on southwest flow since Monday deposited up to 19 inches in Big Cottonwood Canyon, 18 inches in Little Cottonwood Canyon and 18 inches along the Park City ridgeline.

A cold front arriving Wednesday afternoon is expected to push snowfall rates to two inches per hour, with an additional 16 to 25 inches forecast in Little Cottonwood, 12 to 16 in Big Cottonwood and 10 to 13 along the Park City ridgeline by 5 p.m. Temperatures are expected to drop into the single digits Fahrenheit.

In other recent avalanche activity, mitigation teams in upper Little Cottonwood Canyon produced slides up to 32 inches deep and 100 feet wide. A large natural avalanche also ran in Days Fork Tuesday evening, with a D1.5-2 slide reported in Lucky Days on a northeast aspect at 9,500 feet.

Current conditions are available at utahavalanchecenter.org.