A relatively rare cloud formation caused an online sensation in Costa Rica on Tuesday. The rainbow cloud formation was captured by eyewitnesses on the ground and touted as "the end of days" and a "sign of God" by some online.
The cloud was spotted in the communities of San Jose, Parrita, Pavas, Escazu and Hatillo, according to ABC News.
Instead of signifying anything biblical, the cloud formation shown in videos and pictures occurred when a budding thunderstorm decided to put on a hat, which then dazzled in bright sunlight.
The cloud formation that led to the rainbow is known as a "pileus," or "cap cloud." Such clouds occur as a building shower or thunderstorm rises quickly in height, causing the air above it to rapidly rise, cool and condense into a cloud that resembles a hat sitting on top of another cloud.
Meteorologists know that when pileus clouds form, they signify that a storm is quickly gaining strength.
In this case, the pileus cloud included ice crystals, and when visible light from the sun hit those ice crystals, the light was reflected and refracted, revealing a rainbow of colors. This more typically occurs in rain showers when the sun angle is low on the horizon, or a layer of high-altitude cirrus clouds, when rainbows or even halos can form near the sun.
A photo posted by @kevinotway on Sep 16, 2015 at 1:09pm PDT
A photo posted by MarceloCh (@morales2chelo_) on Sep 15, 2015 at 2:45pm PDT
As the Washington Post's Capital Weather Gang blog explains it:
The best way to spot these clouds are during the early stages of thunderstorm development, but you have to be vigilant since they don’t typically last very long. The iridescence can be seen when the sun is positioned behind the building storm clouds so that the refracted light can pass through the pileus and to your eyes.
While some saw the hand of God in this cloud, perhaps it is a reminder to look up more frequently, since the sky dazzles more frequently than you might think.