There is a long history of man looking up into the sky and seeing something so strange that the only option was to declare it extraterrestrial. Who knows how many stories these weather anomalies spawned? Green glowing lights dancing on the horizon, iridescent glowing night clouds, sparkling moon-rainbows and odd, colorful halos in the mist. Water and light and wind can playfully mix together all kinds of beautiful, magical creations.
Which of these rare atmospheric anomalies have you seen?
This unusual weather event is thermodynamically identical to a normal thunderstorm, but with snow instead of rain and the top of the thunderhead cloud low. As with a normal thunderstorm, hail may also fall. Thundersnow is often a part of a severe winter storm or blizzard with winds capable of being above tropical storm force. As a result, visibilities are frequently under 1⁄4 mile with extreme wind chills that can result in frostbite. There is also a greater likelihood that thundersnow lightning will have a positive polarity, which is associated with a greater destructive potential than the more common negatively-charged lightning.
For many years, this scary-movie-lookin' cloud did not have a classification. It was nameless. In 2014, after being first proposed as an officially named occurrence by Gavin Pretor-Pinney of the Cloud Appreciation Society, it was officially entered into the International Cloud Atlas. These apocalyptic looking clouds tend to be low-lying and are caused by weather fronts that create undulating waves in the atmosphere. Varying levels of illumination and thickness can create a truly dark and dramatic cloud cover. They are mostly seen on the Great Plains of the US following thunderstorms.
The real name for this rare weather phenomenon is a circumhorizontal arc. These are caused by light passing through wispy, high-altitude cirrus clouds. They can occur only when the sun is very high - more than 58° above the horizon - in the sky and along the mid-latitudes in the summertime. In order for the conditions to be right, the hexagonal ice crystals that make up these cirrus clouds must be shaped like thick plates with their faces parallel to the ground. When light passes through, it refracts, or bends, in the same way that light passes through a prism. If all the crystals are lined up just right, the whole thing lights up like a rainbow.
Also known as night clouds, noctilucent clouds - if you see them at all - form in the summer months at latitudes between 50° and 70° north and south of the equator. The Sun has to be below the horizon, but while the clouds are still in sunlight. They are the highest clouds in Earth's atmosphere, located in the mesosphere between 47 to 53 miles up. They are too faint to be seen during daylight. Regular clouds in the lower atmosphere form when water collects on particles, but these mesospheric clouds seem to form directly from water vapour and dust particles. The occurrence of noctilucent clouds appears to be increasing in frequency, brightness and extent.