Cloud Index: Defining types of clouds and their unique characteristics

Weather Glossary

Clouds are typically sorted and identified by characteristics such as their height in the sky, texture, and the type of “weather” they do or do not produce. A good way to get better at identifying clouds is to practice. Make sure to always look up and frequently take pictures of those clouds. Use those pictures to compare what is here and other cloud pictures to help identify those clouds.

This cloud index is composed of photos taken by us, your WROC Weather Team, with one exception on the more difficult to capture cloud types. First, we’ll look at the 10 basic cloud types:

Upper Level Clouds

Cirrus, Cirrocumulus, and Cirrostratus 

This first group of clouds are the highest in the troposphere with the prefix “cirro” meaning “curl.” Cirrus clouds are thin and wispy in appearance that often look “hair-like.” They contain ice crystals that occasionally provide unique colors to the sky, and are typically white in appearance. 

Cirrus
Photo: Christine Gregory

Cirrus
Photo: James Gilbert
Cirrocumulus
Photo: James Gilbert
Cirrostratus with sun dog
Photo: Christine Gregory

Mid-Level Clouds

Altocumulus, Altostratus, Nimbostratus 

These clouds are considered to be mid-level clouds, despite their prefix “alto” meaning “high.” They usually are composed mainly of water droplets and can take on many appearances. Altocumulus clouds are usually more white and patch-like while the others are much thicker and more gray in appearance. The exception of Nimbostratus are typically considered to be more “low-level” due to its lowering base.

Altocumulus
Photo: Josh Nichols
Altocumulus
Photo: Christine Gregory
Altostratus
Photo: National Weather Service
Nimbostratus
Photo: Christine Gregory

Low-level clouds

Cumulus, Cumulonimbus, Stratocumulus, Stratus

The lowest forming clouds in the sky with a multitude of characteristics. These clouds are also composed of water droplets and are unique in that they can stretch vertically very high into the troposphere, while others remain lower and more flat.


“Fair Weather” Cumulus
Photo: James Gilbert
Cumulonimbus
Photo: Christine Gregory
Stratocumulus
Photo: Christine Gregory
Stratocumulus
Photo: James Gilbert
Stratus
Photo: James Gilbert

There are come cloud types that are just too unique to fit into one specific category. Here are some of the more rare and unique types of clouds:

Mammatus clouds appear pouch-like and are often found on the underside of thunderstorm anvil clouds. They form by air that sinks instead of rises as it typically does to form clouds.

Mammatus
Photo: Christine Gregory
Mammatus
Photo: James Gilbert

Shelf clouds form on the leading edge of thunderstorms. They form as a result of strong, cool air being pushed out ahead of the storm known as a a “gust front” as it meets warm, moist air to form the low lying cloud base.

Shelf Cloud
Photo: Christine Gregory
Shelf Cloud
Photo: Eric Snitil

Lenticular clouds are “lens-like” clouds that typically form downwind of a mountain, but sometimes form elsewhere when stable, moist air flows over something that disturbs the air such as turbulence or shear, ultimately forming its smooth, lens shape.

Lenticular
Photo: Christine Gregory
Lenticular
Photo: Christine Gregory

Cloud Iridescence is not as much a “cloud type” as it is an effect from a mix of sunlight and ice crystals within a cloud, typically cirrus. It’s a colorful, optical phenomenon that occurs as a result of diffraction as small water droplets or ice crystals scatter the sunlight to create the rainbow colors.

Iridescence
Photo: Christine Gregory

Wait too long and you’ll miss these short-lived Horseshoe Vortex cloud formations.. They form as a result of a rising cloud getting caught in rapid horizontal shear in the atmosphere where the conditions are just right. They’re also know to be a form of “fair weather funnel clouds.”

Horseshoe Vortex
Photo: Christine Gregory

Fall Streak or Hole Punch clouds are very hard to spot, but are very cool to look at. They get their name from the hole or gap like appearance they take on when something disturbs the air such as a plane or other aircraft. They usually are found to occur in “alto” or “cirro” cumulus clouds.

Fall Streak/Hole Punch
Photo: Christine Gregory

Scud clouds can often be mistaken as funnel clouds for their ominous appearance, but are simply a type of fractus clouds that occur. They’re essentially cloud fragments that form as a result of warm, moist air rising into the atmosphere, and are known for their ragged and wispy appearance.

Scud
Photo: Eric Snitil

Wall clouds are “lowerings” from the base of a rotating thunderstorm called a supercell, and are associated with producing funnel clouds and tornadoes.

Wall cloud
Photo: Christine Gregory

The Kelvin-Helmholtz cloud, or as Eric wanted to call it-the “crown” cloud, forms as a result of vertical shear instability. This occurs when air is moving at different speeds at increasing heights in the atmosphere, and disturbs the clouds to form these “tail-like” tops to them.

Kelvin-Helmholtz
Photo: Eric Snitil

Sun Dogs are another example of an effect on clouds and sunlight. These rainbows in the sky form as a result of the diffraction of hexagonal ice crystals in cirrus clouds, usually found in concentrated patches at a 22 degree halo around the sun.

Sun Dog
Photo: James Gilbert

Crepuscular rays are shafts of light that form as the sun sets, and radiates from the position of the sun into the western sky.

Crepuscular rays
Photo: Christine Gregory

Some TIPS on how to identify clouds and watch for rain HERE, and you can check out a more in-depth description of some of these cloud types HERE.

Want to share your cloud pictures with us? Share them with us on social media! Our Twitter handles below:

@WxChristineG

@JamesGilbertWX

@EricSnitilWx

@wnywxguy

Copyright 2021 Nexstar Inc. All rights reserved. This material may not be published, broadcast, rewritten, or redistributed.

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