What happened
While performing a landing to the northeast on a frozen slough, the pilot of the aircraft observed a football-sized clump of dirt protruding from the ice directly in front of the airplane following touchdown.
In an effort to avoid hitting the obstacle, the pilot applied full left rudder. While this maneuver caused the nose of the aircraft to pivot approximately 20 degrees to the left, the actual ground track of the airplane remained in a straight line. Consequently, the right ski struck the dirt clump.
The impact caused the right main landing gear to collapse, which subsequently led to the right wing striking the surface of the frozen slough. The accident resulted in substantial damage to the fuselage, the leading edge of the right wing, and the right wing main spar.