Radiation or ground fog is most commonly seen early in the morning following cool, clear nights and, usually, in low lying areas like river and stream beds that offer sources of moisture.
At night, air cools. The greatest cooling occurs when there are no clouds to reflect the earth's heat back downward (as seen in this early morning photo).
Colder, heavier air then sinks into low spots like river valleys or depressions like East End Park's large meadow. Since colder air holds less moisture than warm air, the moisture in the air condenses. As the relative humidity approaches 100 percent, fog becomes visible.
Fog is nothing more than a cloud that hugs the ground, although fog and clouds are formed in different ways. Fog is formed by sinking air. Clouds are formed by rising air. The base of clouds forms where the air cools to its dew point (the point at which water vapor in the air begins to condense).
The best time for taking pictures of fog is just before sunrise. As soon as the rising sun pokes over these trees, it warms the air enough to lower the relative humidity. The fog disappears in a matter of minutes.
With more than 2.5 miles of Lake Houston shoreline, East End Park offers many opportunities for taking pictures of fog and in fog.