The pilot reported that while landing following a night instrument flight, on a known contaminated runway and employing aerodynamic braking, the airplane contacted a snow and ice patch and veered to the left. The airplane continued left until it contacted an unplowed snowbank on the left side of the runway and nosed over coming to rest inverted. The airplane sustained substantial damage to both wings, both ailerons, the vertical stabilizer, and rudder. The pilot reported that there were no preaccident mechanical malfunctions or failures with the airplane that would have precluded normal operation. The pilot reported that prior to the flight he had filed and instrument flight plan and was aware of a Notice to Airmen (NOTAM) that at most 10% of the runway had compacted snow. An area 60-ft wide was plowed and swept.