Final answer:
When warm moist air flows over a colder surface, it may form condensation fog, which is a type of cloud composed of tiny water droplets or ice crystals close to the ground.
Step-by-step explanation:
When warm moist air flows over a colder surface, it may form fog. Fog is a type of cloud that is composed of tiny water droplets or ice crystals suspended in the air close to the ground. It occurs when the warm moist air cools and condenses, forming a layer of fog.
For example, when warm air from the ocean flows over a cool land surface, such as in coastal areas, the air cools down and forms fog. This is known as coastal fog. Another example is when warm air flows over a cold body of water or snow-covered ground, causing the air to cool and form fog.
In summary, the type of fog that may form when warm moist air flows over a colder surface is condensation fog.