The airplane nosed over during the landing roll on a sandbar near Snohomish, Wash., at about 1700 Pacific time. Visual conditions prevailed; the aircraft was substantially damaged but the Private pilot, the sole occupant, was not injured. The flight departed from Everett, Wash., about 45 minutes prior to the accident. The pilot later reported he was intentionally landing on this sandbar, as he has done before. During the landing roll and braking action, the tail came up and the aircraft nosed over, coming to rest inverted. The pilot reported no mechanical failures or malfunctions with the aircraft at the time of the accident.