On June 27, 2002, at 0436 central daylight time, a Beech BE90, N911ND, operated by Weather Modification, Inc., sustained substantial damage when it hit a deer during landing roll and the left main landing gear subsequently collapsed. The airplane veered about 150 feet off the left side of runway 34 (4,400 feet by 75 feet, asphalt), at the Roseau Municipal Airport (ROX), Roseau, Minnesota. The pilot, copilot, and two medical personnel reported no injuries. The 14 CFR Part 91 positioning flight departed Hector International Airport, Fargo, North Dakota, at 0350, and was en route to ROX to transport a medical patient. Visual meteorological conditions prevailed. The flight was on an instrument flight rules flight plan. According to the pilot's written statement, he flew direct to ROX at 13,000 feet and attempted a landing on runway 16. The pilot reported that he touched down approximately 1,000 feet from the threshold. He stated, "Deer impacted left side of aircraft immediately after touchdown. Left gear collapsed. Aircraft yawed to left and departed runway. Full right rudder did nothing to control direction of aircraft." According to the pilot, the aircraft came to a rest in a ditch approximately half- way down the runway on the east side, about 50 yards from the edge of the runway.