What happened
The incident occurred following the delivery of equipment to a lakeside cabin. The pilot then began taxiing the floatplane on the water surface, preparing for departure from the lake. Conditions were characterized by gusty winds blowing in the same direction as the aircraft's intended path.
During the taxi phase, the operator accelerated the aircraft to fly over the step, a technique used to reduce drag and increase speed before takeoff. While maintaining this fast taxi configuration, the pilot observed the intensity of the wind gusts. In response to these conditions, the pilot retarded the throttle to reduce power.
Immediately following the reduction in thrust, the aircraft lost lift and pitched forward violently. The nose of the floatplane submerged into the water, causing the aircraft to capsize. The floatplane came to rest completely inverted beneath the surface.