DRIVER WAS OPERATING TRUCK IN HEAVY RAIN. HAUL ROAD WAS VERY SLICK AND TRUCK SLID SLOWLY INTO BERM AT STEEP ANGLE, THEN TURNED OVER. DRIVER CUT LEG WHILE CLIMBING OUT OF TURNED-OVER TRUCK. ALSO SUFFERED LUMBAR STRAIN. TAKEN TO E.R. AT DOCTOR'S HOSPITAL FOR TREATMENT WHERE HE RECEIVED SUTURES.