A fogbow is a very similar to a rainbow; however, as its name suggests, it appears as a bow in fog rather than rain. It is also a rare phenomena too. Small water droplets create a fogbow. Very weak colors are seen in a fogbow. It has a bluish inner edge and a reddish outer edge.
Since the water droplets are very small, the fogbow appears white, which is why it is sometimes white rainbows. When the droplets forming it are almost all of the same size the fogbow can have multiple inner rings, or supernumeraries, that are more strongly colored than the main bow. Unlike a rainbow, fogbows normally appear as a band of bright white, sometimes with hints of red or blue. Because of these differences, fog bows are often referred to by other names – cloud bows, white rainbows or ghost rainbows.
When viewing a fogbow from the air looking down, such as when you’re in an airplane, it is called a cloud bow. Mariners sometimes called his phenomena sea dogs. When a fogbow is seen at night, it is called a lunar fog bow.
A fogbow has the same direction as a rainbow so that the sun would be behind the viewer and the direction would be into the bank of the fog. Its outer radius is slightly less than that of a rainbow.
Your best chances of catching a fogbow are when the Sun is shining brightly and the fog is thin – they’ll appear as the sun breaks through the fog behind you. You’ll often find fogbows as the cool sea mists roll in over the ocean or as fog makes its way down a hillside or mountainside. And, if you happen to be in the middle of a fog or a cloud – say, in an airplane – you might see a full circle rather than an arch as seen below.
On rare occasions, you might see a solar glory or a Brocken spectre within a fog bow. Glories look just like halos, and they’re normally centered on a Brocken spectre or an object within the fog. These colorful rings are created by sunlight reflecting off water droplets in much the same way that rainbows and fogbows are created. A Brocken spectre is a spooky phenomenon that looks like a ghost within the fog. These shadowy shapes are named after a peak within Germany’s Hartz Mountains where Brocken spectres are commonly seen. Brocken spectres are caused by a shadow thrown on the fog – either your own, or that of a nearby object.
Till Next Time,