Earlier, when technology was not muchly advanced, people considered fog as clouds touching the ground. But you must have noticed it forming in places other than open areas. It amazes me how fog forms in inlets. Have you seen it? Do you know the reason why fog forms in inlets? Have you been to bays? Can you tell why fog forms in bays? Let’s begin and find the answers.
1. What is Fog?
A visible aerosol or suspension of fine solid particles or liquid droplets in the air that consists of tiny droplets of water or ice crystals suspended in the air is known as fog. It is considered a type of low-lying cloud. Check out the 12 facts about fog breath.
2. Why is Fog called Cloud on Land?
Scientists mentioned that the formation of clouds and fog is similar and thus, fog can also be considered a form of a cloud. Therefore, calling it clouds on land is not wrong.
3. How Fogs form?
When water vapor or water in gaseous form condenses, you can see fog. All this happens due to the phenomenon of condensation. Whenever there is a difference in temperature between the air and ground, fog is formed. Infrared cooling and advection are the processes by which fog is formed. Must read how is dew formed?
4. What is meant by Condensation?Photo by Wenniel Lun on Unsplash
The process of conversion of the gaseous state into liquid is termed condensation. It is the opposite of evaporation and takes place when the warm air of the atmosphere comes in contact with the cold surfaces. This leads to the formation of tiny water droplets.
Before moving towards why fog forms in inlets, take a look at this example: the water droplets you see on the glass surface that is filled with ice water are the result of condensation. To know more, you can check out condensation examples in real life.
5. How does Fog form by Infrared Cooling?
This process takes place when seasons change from summer to fall and then to winter. During summer, the ground absorbs water and when the air passes over it, the water again becomes moist and warm. During the season change, this warm moist air prevailing on the ground collides with the cool air that is blowing. When hot warm air collides with cold air, condensation takes place, resulting in the formation of fog. (See Why is it more Humid at Night?)
6. How does Fog Form through Advection?
This type of fog is basically wind-driven. In this process, warm air is pushed by winds across a cool surface, and then it condenses into fog. In this situation, either the warm air is blown to a place with cooler surfaces, or the warm air is made to pass over any cold surface. This type of fog is formed over water bodies, mostly. (See What Is Humidity?)
7. What is an Ideal Temperature for Fog Formation?
The fog formation calls for a temperature difference between air and dew points. The process of condensation and fog formation takes place when the dew point spread is almost less than 5° Fahrenheit. (See What is the Temperature of Water at Room Temperature?)
8. What are the Ideal Conditions for Fog Formation?Photo by Joseph Daniel on Unsplash
The wind is the main component of fog formation. High-speed winds and light winds both work in fog formation. A light wind allows the air layer near the surface to remain saturated. High winds lead to the mixing of air prevailing at the surface with the air at higher altitudes. However, in the absence of winds, instead of fog, dew will form. In the next segments, you will learn about the inlets and why fog forms in inlets, so read on. (See What is a Cold Front?)
9. What is an Inlet?
A long and narrow indentation of the shoreline, usually a small bay or arm of the shore which leads to an enclosed saltwater body, is termed an inlet. It can also be defined as a bay or recess in the seashore, lake, or river. For example, the Burrard fjord in British Columbia, Canada is an inlet. (See When does Snow stick to the Ground?)
10. Why Fog forms in Inlets?
This water body faces evaporation during the daytime and throughout the summer. When the warm air floating over the atmosphere comes in contact with the cold air prevailing at the surface of an inlet, condensation takes place. This is why fog forms in inlets. (See 16 Snowing in the Mountains Facts)
11. Why Fog forms in Bays?
Advection fog is formed over bays. This happens when the moist air moves over a colder surface, like ships, shores, trees, etc. near the bays. The situation can be the opposite too when the warm air from the island moves towards the ocean or bay water and comes in contact with the cooler air prevailing over it. This causes condensation and the formation of fog. (See How many Degrees is considered Cold?)
12. When does Fog Form in Inlets and Bays?
Since you are aware of why fog forms in inlets, you must know that fog formation takes place with changes in temperature. You can witness fog near inlets and bays mostly during the early morning and early evening hours. But the time period is not limited to dawn or dusk and can persist for longer periods. Also, check out why is grass wet in the morning?
13. Can Fog Form during Summers?
In summer, as the humidity levels rise to 100%, it causes the formation of fog. Because when the temperature drops close to the dew point and the cold air is mixed with warm air, it leads to fog formation. (See Why is it Hotter in Summer?)
14. Why does Fog mostly form on Clear Nights?
Besides answering why fog forms in inlets, note that it happens not only the clear nights but on clear nights after rain or snowfall. During these two forms of precipitation, the land or ground is saturated. After this, the moisture from the ground will evaporate and clear skies increase the evaporation process. If the clear sky is followed by a light wind, it will keep the moisture near the surface restricting its mixing up with drier air at higher altitudes. (See How does Radiation Fog develops in the Valley at Night?)
15. What are Different Types of Coastal and Sea Fogs?
Fog formation is necessarily not in wet areas because dry areas and dry air can lead to fog formation as well. It happens even when the humidity is 70%. Take a look at the brief description of different types of fog formed near coasts and seas to know why fog forms in inlets.
- Arctic Sea Smoke: This fog is misty and mostly like smoke and occurs only when the air is freezing. In such situations, the water is not condensed into water droplets but into columns of freezing water.
- Garua Fog: Garua fog is a type of transparent mist that is formed when the fog travels from the nearby coasts towards inland and comes in contact with a hot air area. The water particles of the fog are shrunk by evaporation, making this type of fog almost invisible.
- Sea Smoke: This type of fog is formed when cold air passes over moist land or warm water. It is known as the evaporation fog or steam fog.
So, today you got to know how fogs form, along with why fog forms in inlets and why fog forms in bays. This natural phenomenon is mostly altered by the temperature, winds prevailing, and rate of evaporation. (See How Fast does Rain melt Snow?)