N993S

While maneuvering in mountainous terrain about 700 feet above ground level, the airplane encountered "an extreme clear-air [sic] microburst." The pilot was unable to control the descent rate and executed an off-airport landing. During the landing, the nose gear collapsed and the airplane nosed over. The airplane sustained substantial damage to the vertical stabilizer and both wings. Postaccident examination of the airplane by Federal Aviation Administration inspectors revealed no evidence of mechanical malfunctions or failures that would have precluded normal operation. Attempts to obtain a completed Pilot/Operator Aircraft Accident Report (NTSB Form 6120.1) from the pilot were unsuccessful.