Pretty sure this image just takes advance of forced perspective. What we're actually looking at is a long cloud of insects flying more horizontally (probably with a slope) directly above the head and in front of the photographer. By focusing on the horizon she's forced the false perspective of the apparent "tornado" cloud. You can tell that's not what's really happening by the scale of the insects themselves. They're largest at the top of the screen, which would be appearing from right over her head. They get smaller toward the bottom of the pic, which is actually farther away.