THE PILOT OF THE SKI-EQUIPPED AIRPLANE STATED THAT WHILE HE WAS MAKING A WIDE LEFT TURN, IN PREPARATION FOR A RUNNING TAKEOFF ON THE FROZEN LAKE, THE AIRPLANE'S NOSE AND RIGHT WING SUDDENLY HIT THE SURFACE. THE RIGHT MAIN LANDING GEAR BOX WAS TORN FROM THE FUSELAGE. THE SURFACE OF THE FROZEN LAKE WAS COVERED WITH ABOUT 2 FT OF FRESH SNOW, WITH SOME HIGHER DRIFTS.