Northwest Flight 307 originated in Washington at 12:30 destined for Winnipeg, Canada. Scheduled intermediate stops included Detroit, Madison, Rochester and Minneapolis. Flight 307 arrived over Rochester at 20:23, and because there was light freezing rain, did not land and continued to Minneapolis. At 20:41 the tower advised Flight 307 of existing, weather conditions: a precipitation ceiling of 900 feet, visibility variable 1/2 to 3/4 of a mile, and the wind from the north at 27 mph with gusts up to 40 mph. The tower informed the flight that there had been two electric power failures at the field, and that if no further communication were received from the tower, it would be in all probability the result of another power failure. After reporting over the outer marker, which was 4.7 miles south of the approach end of runway 35, the Martin was cleared to land. The approach was probably flown visually and the airplane descended below the ILS glide path. At a height of 70 feet the airplane struck a flagpole near the entrance of the National Soldiers Cemetery. This pole, probably obscured by snow, was 4,180 feet south of the approach end of runway 35 and 650 feet west of the center line of that runway. From this point the Martin turned left, passing over the airport control tower which was located 1.6 miles north of the flagpole. The aircraft then flew northwesterly 3.8 miles where the left wing section became totally separated from the aircraft and dropped to the foot of Washburn Park water tower. Then the aircraft progressed westerly an additional 2,640 feet before striking the residence located at 1116 West Minnehaha Highway. A fire which started immediately after the crash consumed the house and much of the aircraft wreckage. Two of the occupants of the house were killed. PROBABLE CAUSE: “The attempt to complete a landing approach by visual means during which time visual reference to the ground was lost.”