What happened
After obtaining a weather briefing and filing an IFR flight plan with an Automated Flight Service Station (AFSS), the pilot departed and climbed to a cruising altitude of 8,000 feet, remaining above the cloud layer. While en route, the pilot encountered strong headwinds and requested a descent to 6,000 feet. Air Traffic Control (ATC) approved an initial descent to 7,000 feet.
During this descent, the aircraft entered the clouds and encountered severe turbulence and icing. Once below the cloud layer, the pilot was unable to maintain altitude, necessitating a forced landing at a nearby airport. During the landing phase, strong winds blew the airplane off the runway and into the runway lights. At the time of the event, reported winds were 250 degrees at 14 knots, gusting to 24 knots.
Prior to the flight, the AFSS weather briefing had included an AIRMET for light to moderate mixed/rime icing in clouds and precipitation from the freezing level up to 10,000 feet, as well as isolated severe icing. The briefer also noted that the freezing level along the route was between 2,000 and 4,000 feet and provided a forecast for strong westerly winds, including winds at 9,000 feet from 280 degrees at 38 knots.