It was reported by the pilot's son that prior to departing for the flight, the pilot was aware of the poor weather conditions along the route of flight. The son and another pilot were flying in a twin engine airplane, and the father was in the single engine airplane. The son stated that his father took off about eight minutes before their flight and turned toward the northwest, while the son took off and turned to the northeast to follow the valley south. The son reported that the weather front was running across the valley and that light snow was falling and visibility was poor at the time. The wreckage was found along the west side of the valley near rolling hills approximately seven miles south of the airport. A witness reported that he heard the crash but could not see it due to the falling snow. Post crash investigation did not reveal evidence of a mechanical failure or malfunction.