ORLANDO, Fla. – Several communities that saw storms Tuesday night caught a glimpse of a rare and beautiful optical phenomenon.
These are known as pileus clouds with iridescence.
Lisa M. Orlando
I do believe this is one of the most uniquely beautiful things I have ever seen! A rainbow-tipped cloud tonight, seen from my backyard after a rain shower. Lisa Miller
There are actually two things going on here.
The first was the formation of pileus cloud. These clouds form above a larger and growing cloud, such as a thunderstorm cumulonimbus cloud.
They form when strong updrafts force moist air above the growing cloud, causing it to condense into a wispy cap-like shape.
Typically, these clouds are short-lived as the main cloud that is rising consumes the pileus cloud.
The second part, the rainbow part, is cloud iridescence.
It occurs when sunlight is diffracted by tiny water droplets or ice crystals in a thin, smooth cloud. In this case the thin, smooth cloud was the pileus cloud over the developing thunderstorm.
The diffraction (when light bends around the particles) creates a vibrant display of colors that appear to be a rainbow.
These tend to form on hot, humid days with rapidly developing thunderstorms. The sun also needs to be at a lower angle for the light to pass through the atmosphere and reach the clouds.
Central Florida was dealing with record heat Tuesday, with storms firing around sunset.
Perfect conditions were met to catch not one, but two atmospheric phenomena at the same time.