in this video we're going to look at all seven types of fog that you should know as a pilot we'll dive into exactly how and where they happen so that you can avoid getting caught by it I can you name all seven of them my name is Greg I've been an fa fly instructor for over 20 years and I'm also the lead instructor at pirot Institute the online school that helps you achieve your Aviation dreams first what is fog in a nutshell fog is a low-lying cloud it's tiny little water droplets that are near the Earth's surface that cause reduce visibility fog forms when the air temperature reaches the dueo it's very important this causes the water vapor to become visible droplets fog very much like other clouds is going to hamper visibility and is going to directly impact visual flying what's the difference between other types of visibility restriction like Mist for example well if the visibility is less than 5/8 statute mile then it's called fog if the visibility is greater than 5/8 statute mile then it's going to be called Mist now we classif ify the different types of fog according to how they form which brings us to the first type of fog it's called radiation fog now radiation fogs usually forms at night when the surface cools causing the air above it to cool as well now if the air has enough moisture this cooling will lead to saturation and then form fog now this type of fog is also known as ground fog if it's less than 20 ft in thickness you'll find radiation fog early in the morning when the surface is coldest now it tends to dissipate soon after sunrise and as the ground is going to warm now because of this many people call radiation fog morning fog now there are three different conditions that lead to the formation of radiation fog the first is a clear sky now clouds will trap the heat from the surface causing it and the air above it to stay warmer so a clear sky is going to cause the maximum amount of cooling effect now second we need to have calm winds this allows for a uninterrupted cooling of the air now third we need need to have a long night a long nights just like those in the winter they allow for the surface to cool and then for the air to cool above it for the longest period of time now High Press system often create the conditions that lead to that radiation fog and the next type of fog is called advection fog now advection fog forms when the warm and moist air moves over a cooler ground or over water now it is relatively shallow and often associated with a temperature inversion unlike radiation fog inection fog can actually form with strong winds and also with cloud cover now another type of fog that is associated with the wind is called the UPS slope fog UPS slope fog is going to form when the mo air flow is going to go upward over the rising terrain causing it to cool using a method called adiabatic in order for the dint temperature to be reached the agatic is the process that causes the rising air to cool and the sinking air to warm as this type of fog is more common at higher elevations and also can build downward Into The Valleys UPS slope fog can also exist in high wind conditions because well that's going to increase the lift and then also increase the adiabetic cooling next up is steam fog steam fog is also known as evaporation fog and that is going to form when a cold air is going to move over a warm body of water warmer water is going to evaporate into the cooler air above it and then increase the air moisture content when the moist warm air is cooled to the dupoint temperature by the cooler air below it then the warm vapor is going to condense into tiny water droplets and that's going to create fog now this often happens in the early fall or the late spring when the air temperature is going to drop quickly compared to the actual water temperature so what does the steam fog actually look like well it's a wispy tendrils that are rising from the water surface that can resemble Steam steam hence why we call it steam fog now you'll often find the steam fog over bodies of water such as lake rivers and reservoirs okay now things are getting a little colder with freezing fog and Ice fog freezing fog forms in saturated air when the surface temperature is below freezing now the water droplets in freezing fog are actually called super cooled which means that they are in the liquid state despite being below freezing temperature so the reason they do not freeze in the air is because they don't have the nucleus so core around which the Ice Crystal can actually form now freezing fog is more common in regions where the winters are really cold especially in The Valleys or any areas where the cold air is going to be stagnant now the freezing temperatures cause the super cold water droplets to freeze on impact with any surfaces and that creates rhyme ice either on the ground or possibly on your wing that's important to differentiate between freezing fog and Ice fog ice fog resembles freezing fog but it consists of tiny little ice crystals and it happens when we have extremely cold conditions well below the 32 fah or the 0° C now freezing fog on the other hand contains liquid water droplets this is going to form around temperatures that are right around or just below freezing the second to last type of fog is called frontal fog frontal fog is going to form during a warm or a cold front passage the warmer rain that falls into the colder air is going to then evaporate as a result the D point is going to rise and then that's going to lead to air saturation now the fog associated with a warm front is called prefrontal and then the fog associated with the cold front is called post frontal frontal fog usually dissipates right after the front passes the last type of fog that you may encounter is called precipitation fog this type of fog is going to form when the rain falls through a cold and dry air bass The increased moisture leads to an increase in due Point causing the saturation and the formation of fog a precipitation fog is associated with a front and can also result from a slower moving cold front from a flying perspective fog is a real pain especially when flying VFR it's not as much of an issue if you're flying IFR check out this uncut video right here from one of our IFR flight with one of our fly instructor and thanks for watching we'll see you in the next one