iridescent Pileus Cloud Observed from Ashburn, Virginia
September 13, 2022
Photographer: Linsday Hank
Summary Author: Lindsay Hank; Jim Foster
The photo above showing a particularly colorful, pileus type cloud was taken from Ashburn, Virginia, as a thunderstorm approached just before 7:00 p.m. local time on August 9, 2022. The camera was facing west, in the opposite direction a rainbow would be seen. Though the pileus itself is mostly hidden by the darker storm clouds, the iridescent colors help to reveal it.
In thunderstorm updrafts, rapidly rising air into a very humid layer may form a silky looking, rounded cloud, called a pileus cloud. If the cloud is in the vicinity of the Sun, and if the cloud droplets are similarly sized, then diffraction of sunlight will produce iridescence. Note that the colors typically observed aren't as attention getting as seen here. Always take care to protect your eyes when looking anywhere near the Sun.
Ashburn, Virginia Coordinates: 39.0438, -77.4874
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