The pilot reported that, during a night cross country flight, the airplane encountered icing conditions while on an instrument approach. The pilot observed about 4 inches of ice had formed on the wing, running about one foot aft. The pilot reported he put the landing gear down about 5 miles from the runway. The pilot continued the approach and stated he broke out of the clouds about 300-400 ft agl and had “minimal control.” The airplane impacted snow-covered ground and came to rest about a half mile from the runway. The airplane was destroyed by a post-impact fire. In an email, the pilot stated the “airplane was in good shape.” At the time of the accident there was an icing AIRMET that covered the location of the accident. The Socata TB21 Pilot Information Manual states “Flight into known icing conditions is prohibited.”