Little Cottonwood Canyon

The Utah Department of Transportation(UDOT) SR-210 and Town of Alta (TOA) Avalanche Infrastructure Study was conducted to evaluate avalanche hazard mitigation options for avalanche paths affectingSR-210and the TOA. The study provided UDOT and stakeholders with options that reduced avalanche hazard and reduced or eliminated explosives fire over the TOA. Both passive and active controls were reviewed, including snow sheds, snow nets, deflection and stopping barriers, stopping walls, artillery, Remote Avalanche Control Systems, helicopter control, hand charging, and skier compaction from lift accessed skiing. Options were evaluated with the objectives of reducing frequency of avalanches reaching the highway and TOA, improving the efficiency of the UDOT avalanche hazard management program by reducing the number and hours of road closures and Inter-lodge restrictions, improving the safety of workers and public during road closures and explosive control, and reducing or eliminating the use of ‘Overhead Fire’ where artillery is fired over the TOA.

A detailed avalanche risk assessment was also completed as part of the Environmental Impact Statement prepared for SR-210 in theLittle Cottonwood Canyon which links Salt Lake City with the TOA. Avalanche mitigation options were evaluated to reduce the risk to the highway including 2-lane and 3-lane snow sheds, the installation of a gondola to reduce traffic volumes, and highway realignments including new bridge construction. DAC is providing detailed design criteria for the construction of snow sheds over three paths, avalanche deflection/guiding berms above the snow sheds, and snow shed construction criteria for loading resulting from avalanche impacts and debris accumulation.