WHILE TRAVELING PART OF INTAKE WITH INSPECTORS WE CAME UPON A ROOF FALL AT SPAD 1424 IN AN INTERSECTION, FALL WAS NOT IN TRAVELWAY. IT WAS APPROXIMATELY 20'X20' COVERING INTERSECTION-THE FAL L WAS APPROX. 50'HIGH AT HIGHEST POINT. NO VENTILATION WAS DISTURBED. AREA WAS DEVELOPED AROUND JAN 02. IT WAS INVESTIGATED