Eye-Catching Iridescent Cloud Pops Up Over Costa Rica

posted: 09/18/15
by: Danny Clemens

A multicolored cloud inspired awe -- and fear -- into residents of Escazu, Costa Rica earlier this week, with one observer fearing that the remarkable cloud signaled the end of the world:

From different angles, the enigmatic cloud assumed slightly different appearances:

IlluOminous perturbations. #escazu #sanjose #costarica

A photo posted by @kevinotway on

#ElcieloExtra?o #escazuCostaRica

A photo posted by MarceloCh (@morales2chelo_) on

Alas, the end of time has not arrived; the striking rainbow of colors painted across the cloud is part of a phenomenon known as cloud iridescence. After a similar iridescent cloud appeared over Boulder, Colo. in 2007, NASA shed (non-iridescent) light on the science behind the beautiful cloud:

"These clouds are formed of small water droplets of nearly uniform size. When the sun is in the right position and mostly hidden by thick clouds, these thinner clouds significantly diffract sunlight in a nearly coherent manner, with different colors being deflected by different amounts. Therefore, different colors will come to the observer from slightly different directions."

A similar, far-less-menacing cloud appeared over South Carolina this summer, taking social media by storm and earning the nickname "Fire Rainbow."


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