Fog

Fog

Fog is usually in the form of stratus clouds that have come in contact with the ground.

Types

Radiation Fog

It is formed on clear nights with light winds. The ground cools at night, and the air in contact with the ground also cools. As this happens, the air temperature is lowered below the dew point. This fog only forums over land, usually only at night and in low areas such as valleys.

Advection Fog

Is formed from warm damp air moving over a cold land or sea surface. It is found most often in coastal areas, usually when moist air from a warm region of the ocean moves over colder waters. It normally last for a few hours because the water is not effected by daytime heating. It can go over land when the circulation is form the sea to a colder land surface.

Upslope Fog

This forms from the cooling of air as it moves up a slope. A light wind going up the slow is required.

Steam Fog

This forms when cold air moves over a warm water surface. Evaporation occurs until the air becomes saturated. It is usually found over rivers and lakes during the autumn.

Precipitation-induced Fog

Also known as frontal fog, it is formed by the addition of moisture to the air through evaporation of rain or drizzle. It is associated with warm fronts. The falling rain saturates the cooler air below it.

Ice Fog

This forms in moist air during extremely cold calm conditions. It is created by the addition of water vapour though fuel combustion.