So how do insects, especially small insects, cope with high winds? (Yes, insects in specific, because arachnids don’t fly. They, at most, balloon.) Do they have enough instincts to hold on tight and wait it out? Is there some bit of fluid dynamics I’m missing?
One of the reasons whitewater rafters avoid such waters is because they can drown in them, which is not an insect’s problem when travelling through the air.
Keep in mind that when they hit something, there is very, very little pressure applied to their body. Area goes up at the square of dimensions and volume at the cube.
Presuming that density is roughly constant, that means that if an insect’s dimensions are 1/100 of a human’s, the area will be 10 000 times smaller but its weight 1 000 000 times smaller. Which means there will be 100 times less weight per unit of area hitting an object at that speed.
The whitewater rafter analogy doesn’t work very well because the rafter is on the boundary between a highly viscous flowing fluid and a less viscous (relatively) static fluid, and would prefer to keep the shiny side up.
The gnat is immersed in the air. A better analogy is a scuba diver 20 feet down in a flowing river. He really isn’t going to mind the flow at all, hardly notices it, as long as it doesn’t smash him into a rock. The gnat doesn’t (and can’t) cope with high winds, it just goes along for the ride unless he hits something.
Q: What is the last thing to go through a gnat’s mind when he hits a windshield?
A: His ass.
A couple of times I’ve had a window seat on a commercial airliner, and watched bugs holding fast to the outside of the window until just a few seconds before liftoff, when the slipstream was probably well over 100 MPH. Tenacious little bastards.