What happened
While operating at approximately 100 feet above the ground, the pilot initiated a downwind turn. During this maneuver, the aircraft encountered a downdraft that pushed the plane toward the ground. In an attempt to recover, the pilot applied full power; however, the engine failed to produce the necessary thrust, and the descent continued.
Due to the low altitude, the pilot was unable to identify a suitable landing site other than a nearby frozen river. The aircraft struck the ice with significant force, resulting in damage to the wings, fuselage, and landing gear. The pilot was not injured during the event.
The investigation
The pilot reported that the engine's failure to produce full power was likely caused by carburetor ice. This ice had accumulated because the engine had been operated at a reduced power setting without the use of carburetor heat.