On June 16, 1996, approximately 1305 hours Pacific daylight time, a Cessna 182, N5686B, being flown by a private pilot, was destroyed in a post-crash fire following the collapse of the nose landing gear upon landing at the Roche Harbor airport, Roche Harbor, Washington. The pilot and three passengers escaped without injury. Visual meteorological conditions existed and a VFR flight plan had just been closed prior to landing. The flight, which was personal, was to have been operated under 14CFR91, and originated from the Arlington airport, Arlington, Washington, approximately 1230. The pilot was interviewed by a deputy of the San Juan County Sheriff's Office (Case number 96-1575) immediately following the accident and reported that "as he approached for his landing on (runway) 24, he encountered a `downdraft' which caused his landing gear to touch down in the soft soil approximately 150 feet short of the end of the runway" and that his "gear dug in and then just broke." During the landing roll, and prior to rolling onto the runway surface, the nose landing gear separated. The aircraft then continued onto the gravel runway. During the ground slide, a small fire broke out. Once the aircraft came to a stop all four occupants exited and the aircraft was subsequently consumed by the post crash fire. The airport manager reported in a telephone conversation that there was a shallow "swale" crossing the primary surface at the approach end of runway 24 and that he estimated the touchdown point of the Cessna as at least 100 feet from the threshold.