WONTHAGGI, Australia, Nov. 4 (UPI) -- Dozens of Australians in the eastern portion of the state of Victoria were startled when a hole appeared to open up in the cloud cover above.
The phenomenon wasn't exactly ominous -- revealing a clear blue sky and producing a rainbow -- but was strange and perplexing enough to inspire social media users to jokingly claim the rapture was nigh. Like most things, this unusual meteorological event has a scientific explanation -- and it's not "aliens," as many tweeters suggested.
"A fallstreak hole is a circular or elliptical gap that can appear in high- to mid-level clouds," meteorologist Linda Lam told the Weather Channel. "There are water droplets in the cloud that have yet to freeze, and once they do (when ice crystals are introduced), the water droplet freezes and grows. As it grows, it begins to fall and a hole is left behind."
In other words, a portion of the cloud cover froze on Monday, above the Gippsland area of southeast Australia, and began to sink, leaving a large gap resembling a hole in the sky. The ice crystals necessary for the formation of the fallstreak hole are often introduced by a passing airplane. The freezing process causes the sinking water droplets to gather and diffract the sunlight, creating a rainbow-like effect known as iridescence.