On March 7, 2001, about 1310 Eastern Standard Time, a Cessna 172S, N574SP, was substantially damaged when it impacted a snow bank during a landing rollout at Dillant-Hopkins Airport (EEN), Keene, New Hampshire. The certificated private pilot was not injured. Visual meteorological conditions prevailed for the flight, which was operating on a visual flight rules flight plan between Lebanon Municipal Airport (LEB), Lebanon, New Hampshire, and Keene. The personal flight was conducted under 14 CFR Part 91. According to the pilot, he checked the weather several times before the flight, and received a NOTAM that Dillant-Hopkins runway conditions were reported as "clear, with patches of packed snow and ice." The pilot decided, "since I had continued instruction throughout the winter months, and had experience in takeoffs and landings on other than dry runways, I felt I was within my personal minimums to safely complete the flight." The airplane departed about 1250, and except for occasional light turbulence, the flight was uneventful. The pilot began monitoring Keene UNICOM and AWOS about 22 miles from the airport, and about 9 miles from the airport, received an advisory over the UNICOM frequency, which confirmed that winds were variable, between 320 and 020 degrees, at 6 knots, and that Runway 02 was open, "with patches of packed snow and ice." The pilot entered the pattern, and flew a normal approach. He landed, with the throttle closed, on centerline, about 500 feet from the approach end of Runway 02. "Touchdown was on the main gear, nose high, at 60 KIAS." Because of the runway's length, and the reports of patches of snow and ice, the pilot kept his feet off the brakes, "and expected a long rollout." About 500 feet into the rollout, "the right main tire lost traction, and the aircraft began to yaw, then slowly veer and skid to the left." He attempted to straighten the airplane out, by increasing right rudder pressure, and considered aborting the landing. However, given the airplane's slow speed, and its proximity to a 4-foot snow bank, he decided that an abort would be unsuccessful. The airplane continued to veer to the left, and hit the snow bank at an approximately 30-degree angle, at a speed the pilot estimated to be about 30 miles per hour. The engine stalled upon impact with the snow bank, an engine mount was bent, and the right wing was "severely bent." Winds, recorded at the airport 5 minutes after the accident, were from 350 degrees true, at 5 knots. Magnetic variation was 15 degrees west. The pilot noted, that in the area where he had lost control of the airplane, the runway had appeared, from the air, to have been covered with packed snow. However, after the accident, the pilot saw that there had actually been three patches of slushy wet snow, and some loose snow had blown onto the runway as well, and not completely melted or compacted. The pilot had 92 hours of flight time.