On June 25, 2004, about 1030 mountain standard time, a Lancair LC-40-550FG (Columbia 300), N6505L, veered off runway 24 during the landing roll at the Show Low Regional Airport, Show Low, Arizona. The private pilot was operating the airplane under the provisions of 14 CFR Part 91. The pilot and one passenger were not injured; the airplane sustained substantial damage. The airplane departed from the Flagstaff Pulliam Airport, Flagstaff, Arizona, at 0950, and was destined for Show Low. Visual meteorological conditions prevailed, and no flight plan had been filed. According to a witness, he attempted to land just prior to the accident pilot. During his landing, he encountered a dust devil, which lifted his Cessna 150 airplane approximately 10 feet. He added power and recovered, then completed his landing. As he cleared runway 24 he radioed a warning to the accident pilot who was on final. As the accident pilot landed, the witness watched the airplane encounter the same dust devil during landing. The wind turned the Lancair to the north, and the airplane traveled off of the right side of runway 24. The nose gear sheared from the airplane, and the right wing was punctured after it impacted the ground. The pilot reported that while he was on final, an airplane that landed prior to him reported encountering turbulence on landing. The pilot looked around the airport and did not see any dust devils. He continued his approach to the airport, and the airplane touched down between 75 to 80 knots with full flaps. As the landing gear contacted the runway, the airplane began spinning to the left. The pilot applied right brake and rudder, attempting to correct the spinning. The spin subsided as the airplane departed the runway and encountered soft dirt. The steering had no effect on the airplane so the pilot decided to let the airplane roll to a stop. As the airplane was rolling, an embankment became visible to the pilot. The airplane impacted the embankment at a groundspeed of about 10 to 20 knots. As the pilot exited the airplane he noted that the windsock was indicating a north wind, whereas during his initial landing approach, the wind was coming from the west. During the entire accident sequence, the pilot did not observe the dust devil as reported by the witness. The reported weather conditions were clear with winds 270 degrees at 7 knots. The pilot reported no mechanical malfunctions or anomalies with the airplane.