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Posted by on Nov 4, 2015 in TellMeWhy |

What Is Fog?

What Is Fog?

Fog is a cloud that forms near the ground. Fog appears when the cold ground chills a warm breeze. The sudden cooling causes the moisture in the air to condense, or form tiny droplets of water light enough to float in the air. Fog is a stable cloud deck which tends to form when a cool, stable air mass is trapped underneath a warm air mass.

Depending on the concentration of the droplets, visibility in fog can range from the appearance of haze, to almost zero visibility. Fog can form in a number of ways, depending on how the cooling that caused the condensation occurred. The sudden formation of fog is known as “flash fog”.

When you walk through fog, you cannot see the separate little droplets, but you can often feel their dampness on your face. Fog may be dense or thin. But when the fog is so thin that it can be easily seen through, we usually refer to it as mist, or haze. Fog disappears when the air warms up or when a brisk wind blows it away.

Content for this question contributed by Kelly Stackhouse, resident of York, York County, Pennsylvania, USA