When water vapor freezes or condolences to form small droplets or crystals in the air, both fog and clouds will form. In this way, both are very similar to one another.
With that being said, they both have distinct differences. For example, clouds can form at a wide range of altitudes, while fog can only form near the ground level. If you’re curious to know what additional characteristics separate fog and clouds, read on!
NOTE: To learn how clouds are formed, read our article “How do Clouds form?”.
Understanding What a ‘Cloud’ is
A cloud is a body of water that you can see and is high in the sky. When water evaporates, it goes in the sky or along the earth’s surface. This all depends on the direction of the wind and the pattern.
If the water vapor is made in the sky and condenses high up then it will create a cloud. It goes around dust and smoke particles to make the clouds. They can also differ in weight and height.
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Understanding What ‘Fog’ is
When condensation happens near the surface of the earth, it creates fog or mist. It is a cloud that has just formed near the surface. What you feel when you walk through fog is what you feel walking through a cloud. The cold temperature and the unclearness are exactly what it would be like.
Fog vs. Mist: What’s The Difference?
Fog and mist are the same thing but have a difference when it comes to unclearness. If visibility is less than 1,000 meters then it is a fog. If visibility is greater than 1,000 meters it is called a mist.
What is Haze?
Haze is different from the previous ones. Haze is tiny, dry particles that aren’t water but are things like dust or smoke. It is dust or smoke that is in the air and invisible to the naked eye. If it is dense enough to cause visibility issues, then it is a haze. These particles can sometimes cause the sky to red, which is seen during sunset.
Types of Fog
There are lots of types of fog, like radiation, advection, valley, and freezing.
Radiation Fog
Radiation fog is when the heat on the surface of the Earth is put in the air during the evening. When the heat is transferred, water droplets are created. This can sometimes be called ground fog as well. It doesn’t go high into the air and is usually at night. The fog that burns off when the morning sun comes is radiation fog.
Advection Fog
Advection happens when it is warm and moist in the air with a cool surface. This is called advection and describes how the fluid moves. The water vapor condenses in this scenario and creates the fog.
It usually happens in warm, tropical areas when the air meets the cool ocean. Usually, Washington to California is filled with advection fog. The California Current is cold and goes along the western coast of North America.
Valley Fog
Valley fog is in mountain valleys, normally during the winter season. Valley fog happens when mountains don’t allow the dense air from going anywhere. It is trapped in the valley. In 1930, it happened in the Meuse Valley in Belgium with particles of air pollution. Over 60 people died from this.
Freezing Fog
Freezing fog is when liquid fog droplets freeze to surfaces that are solid. Mountaintops that have a lot of clouds usually have freezing fog. After it lifts, everything looks like spider webs with a layer of frost.
This usually happens in cold and moist places like Scandinavia or Antarctica. If the air doesn’t have any particles, the water in the air is “supercooled.” This means it is below freezing and can be dangerous when coming into contact with roads and sidewalks.
Super Fog
Super fog is when smoke from wildfires comes together with water vapor to make dense fog. The smoke gives particles for the water vapor to condense on. This is a dangerous fog because it is so dense that you couldn’t see your hand in front of your face. It also creates bad driving conditions.
Note: This can also be considered air pollution. To learn more about different types of air pollution, read our article “8 Different Types of Air Pollution”.