CORPUS CHRISTI, Texas — Clouds are usually a popular weather topic because they can seem like familiar shapes or fun colors. This week, the sky put on a show and our Coastal Bend Weather Watchers captured the view. This week was so picture-perfect, our Weather Watcher of the Week was awarded to more than one Weather Watcher!
What are these clouds and how do they form? Meteorologist Stefanie Lauber has the answers.
Rainbow Clouds
These colorful clouds put on a show over the weekend. The layer of rainbow-colored clouds sat atop distant thunderstorms at dusk. Sometimes you may see just a spot of rainbow in a cloud. The rainbow appearance is known as cloud iridescence.
What causes this feature?
As sunlight passed through the cold ice crystals that make up the cirrus clouds pictured, the ice crystal act as a prism, scattered sunlight into different colors. This is how rainbows form, but what makes rainbow clouds more rare is that the clouds have to be thin, fairly uniform, and catch the light at a particular angle to be seen. Learn more about these clouds here.
Shelf Clouds
These clouds look less friendly. Shelf clouds can be very structure and defined, appearing like a space ship, or have a softer appearance that isn't as intimidating. Photos with these clouds can affectionately be nicknamed 'shelfies' or shelf cloud selfies.
What causes this feature?
Rain inside a thunderstorm cools the air. Cold air is more dense than warm air, so it sinks to the ground and spills outward, ahead of the storm. This is called an outflow boundary or gust front. This is the cool breeze you feel when a thunderstorm is nearby or approaching. As this cold air moves out and ahead of the storm, if pushes warm air upwards. When warm air rises, it cools and condenses into the arcus cloud or shelf cloud seen on the leading edge of a thunderstorm.
What about the beautiful sunsets at 'golden hour'?
Clouds can have a rosy or golden appearance at dusk and dawn in the same what that rainbow clouds are made. The water and ice droplets manipulate the wavelength of sunlight and as a result, we enjoy the rose gold skyscape. This is also what makes storms appear gray and ominous. For more on how clouds get their hue, click here.