Rare rainbow cloud looks like ‘psychedelic skies’ over Virginia. What causes it?
Virginia residents spotted a rare surprise on the horizon on Aug. 9, prompting dozens of photos online.
A vibrant rainbow cloud appeared in the sky, morphing as it rolled over the state.
One viewer said the sight was like “psychedelic skies,” sharing photos of the rainbow peeking out from the top of the cloud.
“Rainbow clouds” appear because of cloud iridescence, according to the National Oceanic and Atmospheric Administration. The small water droplets or ice crystals in the cloud must be relatively the same size and the clouds must be thin for the phenomenon to happen, the agency said.
“Cloud iridescence is relatively rare,” the NOAA said on its website. “Semi-transparent clouds or clouds that are just forming are the ones most likely to have iridescence.”
Normally iridescent clouds wouldn’t occur on such thick, stormy clouds like the one seen in Virginia, according to The Washington Post, if it wasn’t for a certain weather factor - the top of the thick cloud had something called a pileus, the outlet said.
A pileus is a thin portion of cloud that servers as a “cap” or “hood” above thicker clouds, according to the World Meteorological Organization.
That pileus was the reason the rainbow cloud occurred, The Washington Post reported.
“We called them ‘rainbow clouds’ but we understand they are also called ‘iridescent’ clouds with rainbow colors,” Virginia resident Michael Siuta told WJLA. “They say clouds have a silver lining ... but some actually have a rainbow lining!”
This story was originally published August 11, 2022 at 2:59 PM with the headline "Rare rainbow cloud looks like ‘psychedelic skies’ over Virginia. What causes it?."
