UFO or Crazy Cloud? ‘Weird Cloud Atlas’ Helps You Decide
There are way more types of clouds in the world than “big, white, and
puffy,” despite what the drawings of nearly every five year old or,
let’s face it, adult would suggest.
Varying with altitude, moisture
content and how the atmosphere is moving around, clouds come in a vast
array of unusual shapes and sizes.
Some take on undulating forms, like
gravity wave clouds, which arise when a stream of wind undulates up and
down as it flows through the air, with clouds forming at the peaks of
the wave and clearings at the troughs.