Outforia Quicktake: Key Takeaways
- Clouds exist mostly in the troposphere, where 99% of the Earth’s water vapor is present, ranging from surface level up to 65,000 ft (19,812 m) above the ground.
- Low-level clouds occur at ground level up to 6,500 ft (1,981 m), middle clouds occur between 6,500-20,000 ft (1,981 – 6,096.0 m), and high clouds begin at 20,000 ft (6,096.0 m) above the Earth’s surface.
- Cirrus clouds are the highest clouds in the troposphere, forming at 20,000-40,000 ft (6,096.0 – 12,192 m).
- Polar mesospheric clouds are the highest clouds overall, forming in the mesosphere at 279,855 ft (85,300 m) above the Earth’s surface.
Have you ever wondered, how high are clouds?
Most clouds are found in the troposphere from surface level up to 65,000 ft (19,812 m) above the ground. Each type of cloud has a special place in our troposphere, and even beyond!
Low-level clouds occur in the lowest part of the troposphere. The highest clouds in the troposphere occur above 20,000 ft (6,096 m).
Levels of the Earth’s Atmosphere
There are five main levels that make up the Earth’s atmosphere. Each level in the Earth’s atmosphere has different characteristics and weather conditions. The five major levels of the Earth’s atmosphere in order from lowest to highest include:
About 99% of the water vapor that exists in the Earth’s atmosphere is present in the troposphere. This is why most clouds form in this atmosphere layer.
The height of the troposphere can range from 23,000-65,000 ft (7,010-19,812 m).
Seasons and latitude can affect the height of the troposphere. The height of this layer is lowest in the winter and polar regions.
The top of the troposphere can be as low as 23,000 ft in polar regions during the winter. At the equator in the summer, the top of the troposphere level can extend up to 65,000 ft.
The warmest part of the troposphere is at ground level. As you travel higher in the troposphere, the air gets colder. This is why mountain peaks in high altitudes have snowcaps, even during the summer.
Commercial airplanes fly in the highest level of the troposphere around 36,000 ft (10,973 m) above the surface.
At the very top of the troposphere is the tropopause. This is the boundary that separates the troposphere from the stratosphere.
The stratosphere is the next level in the Earth’s atmosphere. Similarly to the troposphere, the height of this layer can vary by season and latitude.
At mid-latitude, the lowest level of the stratosphere is 33,000 ft (10,058 m) above the ground. The top is about 31 miles (50 km) above the Earth’s surface.
The most notable feature in the stratosphere is the ozone layer. The molecules in this layer help protect the Earth’s surface from harmful ultraviolet (UV) radiation.
Unlike the troposphere, temperatures rise the higher you go in the stratosphere. Depending on the season and latitude, commercial planes may travel in the lower level of this layer. This can form contrail clouds. Contrails are lines of clouds created by the exhaust of an airplane.
The only other type of cloud that can form in this atmosphere layer is polar stratospheric clouds (PSCs).
No other cloud types form in this layer because it lacks sufficient water vapor. The air is also very dry in this layer. Most clouds need moisture to form.
The mesosphere is the atmospheric layer above the stratosphere. These layers are separated by the stratopause. Aircraft and weather balloons are unable to operate at the mid to upper-level of this layer.
The mesosphere extends from the top of the stratosphere to about 53 miles (85 km) above the Earth’s surface.
The air in this layer is very dry and cold. Temperatures drop to as low as -130 degrees Fahrenheit (-90 C). The air is also very thin, so humans can’t breathe in this atmospheric layer.
Although no main cloud types form in this layer, there is one special cloud type that forms. Noctilucent clouds, also called polar mesospheric clouds (PMCs), form in the mesosphere near the poles.
The thermosphere extends from the top of the mesosphere to about 311-621 miles (501-999 m) above the Earth’s surface. The thermopause is the boundary that separates the mesosphere from the thermosphere.
You may think that this layer would be colder than the ones we’ve discussed so far because it’s much higher. But as its name suggests, the thermosphere is actually very hot.
Ultraviolet radiation and x-rays heat this layer up to about 932-3,632 degrees Fahrenheit (500-2,000 C) or more. Despite these searing temperatures, the extremely thin air would make this layer feel like freezing to us.
The striking waves of lights called Aurora Borealis occur in this atmospheric layer in higher northern latitudes. They’re popularly known as the Northern Lights.
In the southern hemisphere, Aurora Australis or the Southern Lights also occurs in this layer.
The highest main level in our atmosphere is the exosphere. However, some scientists consider the thermosphere the highest layer. This is because the exosphere is more space-like.
The air in this level is extremely thin. The exosphere extends from the top of the thermosphere and fades into space.
Specific heights for the top half of this layer are debatable. Unlike the other layers, there’s no boundary to divide the top of this layer from outer space.
Some definitions suggest the top layer ends at around 120,000 miles (193,121 m) above the Earth’s surface. This is the halfway mark from the Earth’s surface to the moon.
How High Are Clouds in the Troposphere?
There are three main cloud height levels in the troposphere. These levels help us categorize different cloud species. There are 10 main types of clouds. These main clouds occur in the low, middle, and high troposphere levels.
There are four main types of clouds that occur in the lower cloud level. Low-level clouds occur at ground level up to 6,500 ft (1,981 m). These clouds include:
The lowest type of cloud at this level is stratus. These are low-hanging clouds that can also appear as fog close to the ground.
Stratus clouds form horizontally in layers. They usually occur between 0-1,200 ft (366 m) from the Earth’s surface.
There are two species described as stratus clouds, including:
- Stratus nebulosus: Gray, transparent clouds with little features. Can contain enough moisture to produce light precipitation.
- Stratus fractus: Fragmented pieces of cloud lacking a uniform shape. Often white or light gray and seen drifting lower than any other clouds.
Cumulus clouds are the white, cotton-ball like clouds we see on fair weather days. These clouds come in various shapes and sizes. They’re often a favorite for cloud watchers who like to identify different shapes that these clouds can form.
The four subspecies of cumulus clouds include:
- Cumulus humilis: Patchy white clouds composed of water droplets that are wider than they are tall with a horizontal base and rounded top.
- Cumulus mediocris: Light gray at the base with dome-like tops composed of water droplets. May be arranged in rows called cloud streets according to wind direction.
- Cumulus congestus: Vertical formation with a cauliflower-like shape; may develop into cumulonimbus clouds.
- Cumulus fractus: Less uniform in shape and lacks defined edges. Can quickly undergo changes.
Cumulus clouds can occur anywhere between 1,200 and 6,500 ft (365.8 – 1,981 m). They form as a result of convection. This means that when air becomes warmer, it begins to rise and then cools. Water vapor is produced as the air cools and then condenses, creating this type of cloud.
Stratocumulus clouds can occur from 1,200-6,500 ft (365.8 – 1,981 m). These clouds can vary from white to darker gray.
Stratocumulus clouds usually don’t produce any type of precipitation. A light drizzle may be possible, but it’s uncommon. They’re commonly present with other clouds that produce rainy weather.
There are four subspecies of stratocumulus clouds, which include:
- Stratocumulus stratiformis: Most common type of stratocumulus cloud with a flat base and rounded top.
- Stratocumulus cumulogenitus: Form as a result of cumulus clouds spreading out and clumping together.
- Stratocumulus castellanus: Have the ability to expand vertically and produce light precipitation. May result in the formation of cumulonimbus clouds
- Stratocumulus lenticularis: Rare, lens-shaped clouds produced by atmospheric waves.
Nimbostratus clouds are responsible for gloomy days and continuous precipitation. These clouds can occur anywhere between 2,000-10,000 ft (610-3,048 m).
Nimbostratus clouds are heavily layered and usually cover the entire sky in one area. Since these clouds can extend beyond the low cloud level, they’re also categorized as mid-level clouds. Moreover, nimbostratus clouds don’t have any subspecies like most clouds.
Middle or mid-level clouds occur between 6,500-20,000 ft (1,981 – 6,096.0 m). There are two main cloud types that form within this level, which include:
Altostratus clouds are thin sheets of layered clouds that occur between 6,500-20,000 ft.
These clouds don’t have any features and cover the sky like a thin blanket. They’re not dense enough to block out the light from the sun or moon.
Altostratus clouds are made of ice crystals and water droplets. Like nimbostratus, altostratus are featureless and don’t have any subspecies.
Altocumulus clouds occur anywhere between 7,000-18,000 ft (2,134-5,486 m). They’re white or gray and can form in layers or as rounded clumps called cloudlets. There are four main species of altocumulus clouds, including:
- Altocumulus stratiformis: Small patches of fluffy clouds with flat bases that form close together.
- Altocumulus lenticularis: Referred to as lenticular clouds. Almond or lens-shaped clouds that form over mountains or hills.
- Altocumulus castellanus: Tall, puffy clouds that can form into cumulonimbus clouds.
- Altocumulus floccus: Small cloud patches that lack defined edges. Often accompanied by wispy tails known as virga clouds.
Mid-level clouds can be made up of water droplets, supercooled droplets, and ice crystals as temperatures fall in the middle level. Precipitation from these mid-level clouds is rare. If precipitation does occur, it usually doesn’t reach the ground.
The top level of the troposphere begins at 20,000 ft (6,096.0 m) above the Earth’s surface. This is the last level in the troposphere that includes main cloud types.
The three main cloud types that occur in the upper-level include:
Cirrus clouds form at 20,000-40,000 ft (6,096.0 – 12,192 m). These clouds look like white, wispy waves that curl upwards. They’re the result of dry air rising.
Little water vapor is produced in this process, causing the vapor to turn directly into ice. Cirrus clouds are only composed of ice crystals, which makes them appear very white.
There are five different cirrus clouds species, which include:
- Cirrus fibratus: Lack the hook-like feature of regular cirrus clouds. Appear like a paint brush stroke.
- Cirrus floccus: Small rounded clouds that form in patches with wispy tails.
- Cirrus castellanus: Thin, elongated clouds with flat bases and lightly rounded tops.
- Cirrus spissatus: Larger clouds that are more dense. Often appear more gray with the ability to block out the sun in thicker areas.
- Cirrus uncinus: Very small cloud tufts with more prominent wispy tails or hooks.
Cirrus clouds don’t produce precipitation that reaches the ground. Any precipitation these clouds produce turn into virga clouds.
Cirrocumulus clouds can occur anywhere between 20,000-40,000 ft (6,096.0 – 12,192 m) above the ground. These clouds form in large groups of small cloudlets.
When clustered together, these clouds create a phenomenon called mackerel sky. The name of this phenomenon comes from the fish scale-like appearance these clouds can create. Cirrocumulus clouds consist only of ice crystals.
The four subspecies of cirrocumulus clouds include:
- Cirrocumulus stratiformis: Thin sheets of cloud that have small ripple features.
- Cirrocumulus lenticularis: Elongated cloud streaks with less-defined ripples and a lens-like shape.
- Cirrocumulus floccus: Small cloud tufts clustered together caused by air instability.
- Cirrocumulus castellanus: Small cloud tufts with light ripples that develop vertically.
Cirrocumulus clouds can be a sign that stormy weather is in the forecast. These clouds often appear in clusters. They consist of ice crystals, and sometimes supercooled water droplets.
Cirrostratus clouds can also occur anywhere in the upper troposphere between 20,000 and 40,000 ft (6,096.0 – 12,192 m). These clouds form horizontally in layers.
When present, they cover most of the sky. But they don’t block out the sun or moon because they’re transparent.
They can create a halo phenomenon, which can be observed as a bright ring forming around the sun. The halo-like appearance is caused by sunlight reflecting off of the ice crystals within the cloud.
There are two subspecies of cirrostratus clouds, which include cirrostratus fibratus and cirrostratus nebulosus.
Cirrostratus fibratus covers the sky with a veil-like appearance. Cirrostratus nebulosus are barely noticeable because they lack any prominent features or details. But they may be more noticeable if they create a halo around the sun.
Height of Special Cloud Formations
There are some special exceptions outside of the clouds we’ve discussed thus far. Other clouds form in every troposphere layer, or even outside the troposphere.
Cumulonimbus clouds are one of the main 10 types of clouds that can form throughout every troposphere layer. These towering clouds form vertically.
The base of a cumulonimbus cloud can form in the low-level cloud area between 1,100-6,500 ft (335.3 – 1,981 m). The base is flat and dark gray. This cloud extends through the middle level up to the high level of the troposphere.
The top of a cumulonimbus cloud can reach 60,000 ft (18,288 m) or more. The very top of a thundercloud is called an anvil because it has a flattened appearance.
The three types of cumulonimbus clouds that form include:
- Cumulonimbus calvus: Lighter cumulonimbus clouds with a flat base and rounded top that can produce rain showers.
- Cumulonimbus capillatus: Less structured with wispy features relatable to cirrus and may produce virga or hail.
- Cumulonimbus incus: White or light gray storm cloud that’s reached the tropopause, but thunderstorm development has been interrupted. The top flattens out into an anvil shape.
Cumulonimbus clouds are responsible for heavy rain, thunder, lightning, and hail. When these clouds roll in, you can expect severe thunderstorms. They can also produce funnel clouds that turn into tornadoes.
Polar Mesospheric Clouds
Polar mesospheric clouds (PMCs) are unlike any other cloud type because they form in the mesosphere. They’re also referred to as noctilucent clouds (NLCs).
The name variations depend on where the clouds are observed. These clouds are called PMCs when they’re observed from space. NLCs are observed from Earth.
These clouds form 279,855 ft (85,300 m) above the Earth’s surface. PMCs are restricted to polar regions.
They’re most visible as the sun sets just below the horizon. The leftover sunlight causes these clouds to illuminate in colors of bright bluish-white.
Polar Stratospheric Clouds
Polar stratospheric clouds (PSCs) form high in the stratosphere. They’re also called nacreous clouds. These clouds form in polar regions during the winter. They may be observed in locations near the poles, such as Antarctica, Alaska, and Scandinavia.
Since the troposphere is at its lowest point here, lower PSCs still form in the stratosphere. They occur between 49,100-81,840 ft (14,966-24,945 m) above the Earth’s surface.
These clouds only form when temperatures drop drastically below -108 degrees Fahrenheit (-78 C).
Like PMCs, nacreous clouds are best observed as the sun has just set below the horizon. The remaining sunlight illuminates these clouds with iridescent colors of pink, green, or blue.
How High Are Clouds FAQs
What is the highest cloud?
The highest cloud award goes to the lesser known polar mesospheric clouds. These clouds develop in the mesosphere. This is the highest atmospheric layer that contains any type of cloud.
If you only factor clouds within the troposphere, the highest cloud is cirrus clouds. However, the top of cumulonimbus clouds can surpass the height of cirrus clouds by thousands of feet.
What is the most dangerous cloud?
The cumulonimbus cloud is the most dangerous type of cloud. It can bring in strong thunderstorms with severe winds, lighting and thunder, heavy rain, and hail.
Many thunderstorms last no more than 30 minutes on average. But these clouds can create other severe storms like tornadoes.
Violet winds, flash flooding, and lighting strikes can cause serious damage.
What are clouds made of?
Clouds are made of water. But each cloud contains specific forms of water. Ice crystals are most abundant in high clouds like cirrus.
A mixture of water droplets, supercooled droplets, and ice crystals are common in mid-level clouds. Low-level clouds mainly consist of water droplets, but sometimes have ice crystals.