Shelf Cloud Over Saskatchewan
22.01.2008

Perhaps it's time to go inside. Such thoughts might occur to people witnessing the approach of an impressive shelf cloud. Shelf clouds are typically seen leading thunderstorms, although they may precede any well defined front of relatively cold air.

A Fire Rainbow over West Virginia
30.08.2021

What's happening to this cloud? Ice crystals in a distant cirrus cloud are acting like little floating prisms. Known informally as a fire rainbow for its flame-like appearance, a circumhorizon arc appears parallel to the horizon.

APOD: 2025 August 17 Б Asperitas Clouds Over New Zealand
17.08.2025

What kind of clouds are these? Although their cause is presently unknown, such unusual atmospheric structures, as menacing as they might seem, do not appear to be harbingers of meteorological doom. Formally recognized as a distinct cloud type only last year, asperitas clouds can be stunning in appearance, unusual in occurrence, and are relatively unstudied.

Mammatus Clouds over Mount Rushmore
7.12.2020

What's that below those strange clouds? Presidents. If you look closely, you may recognize the heads of four former US Presidents carved into famous Mount Rushmore in South Dakota, USA. More obvious in the featured image are the unusual mammatus clouds that passed briefly overhead.

Aurora over Clouds
30.05.2021

Auroras usually occur high above the clouds. The auroral glow is created when fast-moving particles ejected from the Sun impact the Earth's magnetosphere, from which charged particles spiral along the Earth's magnetic field to strike atoms and molecules high in the Earth's atmosphere.

A Supercell Thunderstorm Over Texas
13.06.2021

Is that a cloud or an alien spaceship? It's an unusual and sometimes dangerous type of thunderstorm cloud called a supercell. Supercells may spawn damaging tornados, hail, downbursts of air, or drenching rain. Or they may just look impressive.

Meteors Between Stars and Clouds
11.12.2002

Streaking high above diffuse clouds -- but well in front of distant stars -- are sand-sized bits of an ancient comet: meteors. These bits flaked off Comet Tempel-Tuttle during its pass through the inner Solar System about 150 years ago. Far in the background are stars toward the constellation of Ursa Major.

Clouds of Earth and Sky
24.07.2018

If you go high enough, you may find yourself on a picturesque perch between the water clouds of the Earth and the star clouds of the Milky Way. Such was the case last month for one adventurous alpinist astrophotographer.

Iridescent Clouds over Thamserku
8.07.2014

Why would a cloud appear to be different colors? A relatively rare phenomenon known as iridescent clouds can show unusual colors vividly or a whole spectrum of colors simultaneously. These clouds are formed of small water droplets of nearly uniform size.

A Retreating Thunderstorm at Sunset
16.01.2022

What type of cloud is that? This retreating cumulonimbus cloud, more commonly called a thundercloud, is somewhat unusual as it contains the unusual bumpiness of a mammatus cloud on the near end, while simultaneously producing falling rain on the far end.