Boulder, CO - The Four Mile Canyon Fire is burning in rugged, steep terrain west and northwest of the Boulder City limits. A total of 3,500 acres have burned. Multiple structures have been lost and many remain threatened. The fire began on September 6, 2010 in Emerson Gulch located in Four Mile Canyon. Communities impacted by this fire include Four Mile Canyon, Sunshine Canyon, Gold Hill, Sugarloaf, Pinebrook Hills, and Boulder Heights. Approximately 3,500 residents are under mandatory evacuation.