A snowmobiler was killed Friday following a large avalanche in the Smoky Mountains. The Sawtooth Avalanche Center says the rider triggered the avalanche while climbing the slope. Officials with the center say he became caught in the slide and was carried about 600 vertical feet. The rider had deployed an airbag and was found by his partners on the surface. "The avalanche ran into a well-defined gully that acted as a terrain trap, and debris piled up to an estimated depth of 20-30 feet," the center said.