ON 1-6-17 AROUND 7:00 AM, IT WAS SNOWING AND THE ROADS GOT SLICK AND 2 DUMP TRUCKS SLID OFF THE ROAD INTO THE DITCH AND HAD ROAD BLOCKED AT FRONT ENTRANCE, EMPLOYEE WAS GOING DOWN THE ENTRANCE ROAD, APPLIED BRAKES AND STARTED SLIDING AND COULDN'T STOP. LEFT FRONT TIRE HIT THE REAR TIRE ON DUMP TRUCK, THEN LEFT MIRROR HIT THE BED AND BROKE IT OFF. STEERING DAMAGED.