Fog

Radiation fog formation not long after sunrise.

A cloud is a concentrated suspension of tiny water droplets, but when formed at ground level, it is known as fog. There are six types of fog for which are determined by the way it is formed. When moist air is cooled below its dew point by contact with cold land surface which is losing heat by radiation, it is known as radiation fog, and is often seen near sunrise. A cool land mass where warm moist air, often from over water, can cause the air to saturate forming advection fog. All sea fogs are advection fogs as the oceans do not radiate heat similar to land, therefore it never cools sufficiently enough to produce radiation fog. Upslope fog is found within the mountain ranges as well as hillsides. A light wind pushes moist air up to a level where it becomes saturated and condenses, usually a good distance from the peak. The supercooling of water droplets forms a freezing fog. These water droplets remain in liquid state until touching a surface in which they can freeze. When the air temperature is well below freezing, generally near the poles, it causes the fog to be entirely composed of tiny suspended ice crystals.