The commercial certificated pilot was conducting a VFR, Title 14, CFR Part 135, scheduled commuter flight, and was landing on a remote runway during dark night conditions. During the landing roll, the left main landing gear tire struck a snow berm located inside the runway edge lights, along the left edge of the runway, pivoting the airplane to the left. The right wing then struck snow-covered terrain, and received structural damage to the outboard end of the wing.