On September 4, 1999, approximately 1130 Pacific daylight time, a Cessna 182M, N71685, was damaged during a hard landing at Bird 2 Airstrip, Sandpoint, Idaho. The commercial pilot and his three passengers were not injured, but the aircraft, which was owned by an acquaintance of the pilot, sustained substantial damage. The 14 CFR Part 91 personal pleasure flight, which departed Felts Field, Spokane, Washington, about 30 minutes earlier, was being operated in visual meteorological conditions. No flight plan had been filed, and there was no report of an ELT activation. According to the pilot, he was going into a private strip that he had not been to before, and prior to his landing, he was not aware that the runway sloped uphill. Because of the upslope, he misjudged his height above the ground and began his landing flare too late. The delayed flare, along with the upslope of the runway resulted in contact hard enough to damage the propeller, landing gear, and firewall structure.