What is the difference between fog and clouds

What is the difference between fog and clouds?

In the first part of this blog, I’ll discuss the difference between fog and clouds and how clouds form at different altitudes.

In the third section, I will also discuss the change of fog into clouds.

Clouds and fog both occur when water vapor condenses or freezes in the air to create small droplets or crystals, but clouds may form at a wide range of altitudes, whereas fog only forms near the ground.

What are Clouds?

clouds definition

Clouds are the white mist-like formations seen in the sky. These are condensed ice crystals or water droplets that float in the sky.

Clouds arise in various shapes and sizes depending on the meteorological conditions. Rain may fall shortly after the development of clouds.

Clouds may arise at various heights depending on their kind. These floating water droplets are very important in the atmosphere.

For example, they keep the Earth warm at night and give shade to keep us cool during the day.

Types of Clouds

There are ten main kinds of clouds, which are categorized into three levels:

1. High-altitude Clouds 

high altitude cirrus cloud

There are three types of high-level clouds:

  • Cirrus clouds (Ci): These clouds look like white patches in the sky. Cirrus is composed of ice crystals that look brilliant yellow or red before and after sunrise and sunset.
  • Cirrocumulus (Cc): These clouds seem like a thin white patch or sheet piled in the sky with no shading. They appear as random arrangements of minor parts.
  • Cirrostratus (Cs): These clouds are translucent, like a white veil or a sheet of white butter paper. It is not opaque enough to keep the sun out.

2. Mid-Level Clouds 

mid level clouds in sky

Mid-level clouds are classified into three types:

AC (Altocumulus):

They have a grey and white patchwork of layered sheet look. Most of the little pieces placed in this form of cloud are no larger than a little finger’s width.

Altostratus (As):

These are greyish-bluish sheets or layers covering the sky completely or partially. They have a transparent appearance.

Nimbostratus (Ns):

A dark grey cloud layer dispersed by falling rain or snow. They are opaque and prevent sunlight from passing through.

3. Low-Level Clouds

low level cumulus cloud

Low-level clouds are classified into four types:

  • Cumulus cloud (Cu): There are thick clouds with distinct forms that evolve into skyscrapers and structures.
  • The thunderstorm cloud:  Is known as a cumulonimbus cloud (Cb). It is massive, thick, and resembles a mountain.
  • Stratocumulus (Sc): These are layered clouds that are grey or white and have a dark honeycomb look.
  • Stratus (St): These clouds are grey clouds with a thick, homogeneous layer. They create ice prisms, snow grains, and so on.

What is Fog?

fog definition

On the ground, fog clouds might be called.

These are visible aerosols created near the Earth’s surface from microscopic ice crystals or water droplets.

These are known as low-lying clouds and are impacted by adjacent bodies of water, wind conditions, and topography.

Within 1 km, fog may also limit visibility. Fog, like clouds, has many varieties based on how the water condenses on the ground.

Fog is a stable cloud that forms when the relative humidity reaches 100%.

Fog may arise at lower relative humidity levels in certain cases. In such instances, a mild fog forms with little effect on vision.

Fog Types

Various circumstances lead to different types of fog in the atmosphere. Fog forms under different settings and has distinct properties.

Consider these types of fog:

Precipitation Fog

precipitation type fog

This fog forms from precipitation, as the name says. Cold rain creates precipitation fog.

Precipitation fog is more prevalent on warm fronts, although it may occur on slow-moving cold fronts.

When chilly air obtains dew from melting rain, the dew point rises. Such saturation causes precipitation fog.

Steam Fog

Lake fog is steam fog seen surrounding lakes. It forms in September near the Great Lakes.

The air cools quicker than the water as summer ends. Dry, chilly air travels towards the warmer lake, pushing moist air.

This causes steam fog and the second law of thermodynamics.

Radiation Fog 

radiation fog in forest

It’s the most prevalent fog kind. Radiation fog is normal.

It forms when solar heat on Earth’s surface reaches the dew point. Radiation fog forms best after a rainy night.

Radiation fog moistens soil and raises dew points. Winds above 15mph may clear radiation fog.

Advection Fog 

Winds also cause fog. Advection fog best illustrates it. Horizontal winds create it.

This fog forms with the wind. Fog forms when chilly wetness or snow on the ground meets warm/moist air from the south.

It cools the air. It raises dew point, causes humidity, and causes fog.

Freeze Fog

This fog’s name describes it. A freezing fog formed when the temperature dropped below 32°F.

When this fog touches an item, it creates small droplets and rain. Arctic locations have ice fog.

The temperature must be below 14 F. Cool air forms ice crystals.

Upslope Fog

upslope mountain fog

Adiabatically-formed fog. It warms falling air and cools rising air. Hills cause upslope fog.

Moisture blows towards the mountain, cooling and rising the air. Air cooling and rising to the dew point causes upslope fog.

This fog forms at mountain peaks. Mountain ranges with upslope fog are renowned.

Valley Fog

Valley fog, like upslope fog, forms in valleys. It’s caused by the previous night’s rain in the valley.

Dense valley fog is termed tule fog. Valley fog reduces visibility to nothing, making travel risky.

What is the Difference Between Fog and Clouds?

fog and cloud difference

Now that you’ve grasped the fundamental definitions of clouds and fog, it’s time to look at what distinguishes them.

The primary distinction between clouds and fog is that clouds are generated when vapor is converted into liquid and takes the form of small condensed particles.

Fog, on the other hand, is generated when ground air cools, converting vapor to liquid ice or water.

Let us compare clouds and fog to certain parameters.

1. Existence

No matter the climate or the time of year, there are always clouds in the sky that are settled in one place.

Clouds are prevalent throughout the year, however, fog is only noticeable during the winter months.

At this point in the day, there is a possibility that vapor may condense on the ground.

2. Precipitation

Clouds are an essential component of the water cycle because they are responsible for reintroducing water to the atmosphere in the form of precipitation.

There will be no precipitation since fog is not a part of the water cycle and thus does not contribute to the formation of clouds.

Since fog only appears at low altitudes, it cannot be a factor in the production of rain.

3. Significance

rain cloud precipitation

Clouds are very important in the atmosphere since they regulate precipitation and balance the water cycle.

On the other hand, fog has little relevance since it does not contribute to any atmospheric phenomena.

4. Altitude

Clouds may be seen at various elevations. They may be seen as high as 12 miles above sea level or as low as 12 meters above the ground.

Fog is only found on the ground; it is never seen more than 50 meters above the Earth.

5. Density

The density also plays an important role in distinguishing clouds from fog.

The density of clouds is 0.5g/m3, whereas fog is 0.5g/m3 – 0.05g/m3.

Clouds are thicker than fog; however, fog may also become dense.

When Does a Fog Turn into a Cloud?

fog to clouds

As previously stated, both cloud and fog are generated by vapor condensation. Hence fog will eventually convert into a cloud.

At a certain height, fog may transform into a cloud and contribute to the water cycle.

At less than 50 feet, fog forms on the ground and is known as visible moisture.

It is referred to as a cloud when this fog occurs at or above 50 feet.

So, 50 feet is the minimum height at which fog may become a cloud. It is also the thin line that determines the condition of clouds and fog.

For example, when water vapor condenses at or above 50 feet. It will immediately turn into a cloud.

Even at 49 feet, a minor variation in height may create significant changes when vapor condenses. It will be classified as fog.

Final Verdict

What is the difference between fog and clouds?

Fog is a cloud that occurs at ground level and may exist at any height.

Because condensation occurs at ground level in the chilly air, the fog is restricted to the ground level.