What happened
During a takeoff from a lake, the pilot extended 20 degrees of flaps before the aircraft lifted off near the midpoint of the lake. As the aircraft reached an altitude of approximately 20 feet above the water, the stall horn began sounding. The pilot determined that the aircraft would not be able to clear the trees located near the shoreline.
In an attempt to maneuver, the pilot turned the aircraft to the left and reduced power to prepare for a landing while in the turn. This maneuver resulted in a stall of the left wing, causing the aircraft to pitch down and roll to the left. The left wingtip, the corresponding float, and the fuselage all collided with the water. Following the impact, the aircraft sank shortly after coming to rest. The pilot was not injured.