Upon entering into the airport environment, the pilot observed a snow covered runway. He obtained an automated weather observation report (AWOS) for the non-towered airport, with no indication on the recording that the runway was closed. Shortly after touchdown, as the airplane began its roll out, the landing gear entered an area of 12-inch-deep snow and the airplane nosed over. After exiting the airplane, the pilot spoke to the airport manager who informed him that due to a power outage in the area, he had not been able to update the AWOS recording informing pilots of the runway closure due to snow. The airplane sustained substantial damage to the vertical stabilizer and to both wings. The pilot stated that there were no mechanical abnormalities with the airplane prior to the accident.