INDIVIDUAL WAS PLOWING WITH A 966 CAT LOADER. THE LOADER COULD NOT MAKE IT UP THE INCLINE IN THE ROAD SO THE OPERATOR LEFT THE LOADER TO GO TO A BUILDING 100 FEET AWAY TO GET SOME SALT TO SPRE D ON THE ROAD FOR BETTER TRACTION. ALTHOUGH THE SOLES AND LUGS WERE GOOD ON THIS MAN'S BOOTS (RUBBER) THE WARM BOOTS AGAINST THE SLICK ICE CAUSED BY THE LOADER TIRES SPINNING CAUSED A FALL.