Such a tragic accident!  It reminds me once again of the very real, and often unacknowledged, danger of falling into near-freezing water --- which almost all of Alaska's surface waters, even in the summer, very much are.  People in the prime of life have died virtually INSTANTLY from the shock of hitting very cold water!  I fell through the ice of a lake once when I was in my teens, and let me tell you, it is like 10,000 knives stabbing you all over your body all at once!  Of course, one should always be wearing a personal flotation device ("life vest") when going out on the water, but that can only help so much when the temperature of the water is so very cold.