Guarda Streamingcommunity. This is the story of Dave McCoy, founder of Mammoth Mountain. Hear from Dave & Roma McCoy, Warren Miller, Rusty Gregory and other long-time Mammoth insiders in this documentary on the quintessential outdoorsman - how he came to the Eastern Sierra, why he decided to stay, and how he persevered through every obstacle imaginable to follow his firm belief that the steep mountain on the back side of California's remote mountain range could one day be the world's best ski resort.