The pilot received a weather briefing from the flight service station before departing on the accident flight. The weather briefer advised the pilot of forecasted icing conditions along the intended route of flight. The airplane was not equipped with any anti or deicing systems. About 15 minutes after departing while at 14,000 ft MSL, ice began to form on the airplane and the pilot asked for a lower altitude and a ground speed check. The airplane's ground speed was 170 kts. Twenty minutes later the pilot again requested a lower altitude but the controller was unable due to the MEA. About 18 minutes later the pilot asked for a ground speed check and the controller responded, 150 knots and 11 minutes later cleared the flight to 12,000 ft. About 19 minutes later the pilot reported that the airplane was picking up rime ice and again requested a lower altitude. About 7 minutes later the controller reported the airplane's ground speed was 120 knots. About 14 minutes later the pilot reported having problems maintaining airspeed and altitude. Six minutes later the pilot reported that he was unable to maintain the altitude and radar contact was lost 2 minutes later. The airplane collided with upsloping terrain in a wings level, nose down attitude.