On November 28, 1993, at 1030 Pacific standard time, a float equipped Cessna 150H, N22474, collided with rough water during initial climb from the Donnells Reservoir, near Dardanelle, California. The airplane was substantially damaged. Neither the airline transport pilot nor passenger was injured during the personal flight which was originating at the time of the mishap. Visual meteorological conditions prevailed, and no flight plan was filed. The pilot reported that prior to taking off he had looked in the distance and observed water that was a deeper blue color, and that color indicated the presence of strong winds. This was not perceived as being "abnormal" or any hazard to flight because the normal wind pattern for the lake was for the up-canyon blowing winds to increase in strength in the midmorning. The pilot further reported that initially the weather conditions appeared satisfactory for takeoff. However, he could not see the far end of the lake nor the canyon area beyond the lake where his climb would continue. During initial climb, a previously hidden "cell of virga" was encountered. The pilot stated that he turned away from the cell, but encountered strong turbulence and windshear which was accompanied by the downburst. Unable to arrest the sink rate, the airplane contacted the water in a "high rate of descent." The pilot further reported that he was familiar with the accident site area in the Sierra Nevada Mountains, and he had frequently instructed there. No mechanical problems were experienced with the airplane.