Rainbows, sundogs, and Mammatus clouds are three of nature’s most captivating sky displays, each offering a unique glimpse into the beauty and complexity of the atmosphere. Whether it’s the vibrant arc of a rainbow following a rainstorm, the mysterious glow of sundogs on either side of the sun, or the dramatic, pouch-like formations of Mammatus clouds during turbulent weather, these phenomena remind us of the powerful forces at play in the skies above. While they differ in their origins and appearances, they all share the common trait of transforming the ordinary sky into something extraordinary, inviting us to pause and marvel at the natural world.
Rainbows are caused by sunlight reflected on water droplets, forming multicolored arcs that appear directly opposite the sun. These vibrant displays occur when sunlight passes through a water droplet, bends (or refracts), reflects off the back of the droplet, and exits, creating the beautiful colors we associate with rainbows. The spectrum of colors in a rainbow is always in the same order: red on the outside, followed by orange, yellow, green, blue, indigo, and violet. A handy mnemonic to remember this sequence is “ROY G BIV.” Rainbows are typically seen when the sun is low in the sky, such as during a late afternoon shower.
Rainbows have long been symbols of hope and peace, often appearing as the rain subsides. They are mentioned in many cultures and are even tied to various legends, including the idea of a pot of gold waiting at the end of the rainbow.
Sundogs, on the other hand, are concentrated patches of sunlight that appear on either side of the sun, typically at sunrise or sunset when the sun is near the horizon. These light patches are caused by the refraction of sunlight through icy clouds, specifically through hexagonal ice crystals in high cirrus or cirrostratus clouds. While they may look like fragments of a rainbow, sundogs have a distinct pattern: red appears on the inner edge, closer to the sun, while blue and white colors appear on the outer edges. Unlike rainbows, which form a complete arc, sundogs are more like glowing spots that sit about 22 degrees to the left or right of the sun. The term “sundog” has been in use since the early 1600s, though its exact origin remains a mystery.
Interestingly, while rainbows are often seen as a sign of an end to rain, sundogs tend to forecast approaching weather, especially rain or snow. Their appearance can signal a change in weather, with moisture moving into the atmosphere, bringing precipitation in the near future.
Another fascinating weather phenomenon is Mammatus clouds. These pouch-like clouds hang down from the base of larger cloud formations, often forming on the underside of thunderstorm clouds. The name “Mammatus” comes from the Latin word “mamma,” meaning breast, which reflects the shape of the cloud pouches. Although their dramatic appearance may seem ominous, they are typically harmless and are often seen after the worst of a storm has passed.
Mammatus clouds form when cold air sinks and creates pockets beneath the main cloud, giving them their distinctive, lumpy appearance. They are made of ice crystals and can remain visible for 10 to 15 minutes. These clouds are frequently associated with severe weather, such as thunderstorms and tornadoes, and are commonly seen during tornado season in places like Oklahoma. Aviators often avoid flying near Mammatus clouds due to their turbulence.
In addition to their association with thunderstorms, Mammatus clouds have become a favorite subject for weather photography, with their striking patterns and unusual shapes captivating storm chasers and cloud enthusiasts alike.
Together, rainbows, sundogs, and Mammatus clouds showcase the diversity and beauty of our atmosphere. Each phenomenon serves as a reminder of the dynamic and ever-changing nature of the skies above us.
From the vibrant arc of a rainbow signaling the end of a storm to the subtle warning of a sundog heralding incoming weather, these natural wonders connect us to the rhythms of the weather and the intricate play of light in the atmosphere. Whether looking up in awe at a double rainbow or marveling at the sculpted beauty of Mammatus clouds, these moments remind us of the incredible forces of nature at work above.
Read more Nature Notes.
