The pilot was landing the tricycle gear equipped airplane at a remote, unimproved airport, which was surrounded by mountainous terrain. Before beginning his approach, the pilot assessed the wind conditions, and then planned an approach into a 25 to 35 knot quartering headwind. On short final, approximately 20 feet above ground level, a sudden wind shift caused the airplane to descend faster than anticipated. He attempted to arrest the descent by adding engine power, but the airplane landed hard and the right main wheel axle separated from the airplane. The airplane sustained substantial damage to the right wing, aileron and stabilator. The pilot stated that there were no preaccident mechanical anomalies with the airplane that would have precluded normal operation. In the recommendation section of the NTSB Accident/Incident Reporting Form 6120.1, the pilot stated that the accident may have been avoided if a windsock had been present at the airport; he also stated that notes in the Alaska Supplement warning operators of wind shear hazards associated with the terrain surrounding the airport would enhance safety.