So that stuff you are seeing is FOG. No need to worry, no need to panic, once again, that's FOG.
Did ya know then, in most all driving simulators drivers facing heavy simulated fog tend to speed up. WAY up. Extrapolate (yes, 10¢ word) that out to real life conditions and maybe we can see why so many bad accidents happen in fog. Not just the blind driving but the higher speed.