Over flat terrain, such as in Chicagoland, flash flooding often takes the form of ponding of water in low-lying areas. A condition that occurs when water overflows the natural or artificial confines of a river or other body of water, or accumulates by drainage over low-lying areas. A flash flood is rapid flooding that develops within minutes or hours, whereas a flood develops gradually over a period of days, or longer. The difference is in their suddenness. The name originated in the Alps.
Fog is literally a cloud on the ground.
A fairly well-defined mass of fog observed at a distance, most commonly at sea or over a very large lake. The term is not applied to patches of shallow fog. In some instances the dripping is as heavy as steady light rain, as sometimes occurs among the redwood trees of northern California. A light breeze that blows from forests toward open country on clear calm nights. When used as a prefix, the form fracto- is used, as in fractostratus or fractocumulus.