Yosemite Moonbow

Aristotle wrote about them. Benjamin Franklin knew of them. Naturalist John Muir urged people to seek their beauty in Yosemite Falls. What caught the attention of these great men? Moonbows.

One of my favorite memories of Yosemite National Park was going on a moonbow quest. The campfire embers had quieted after a night of singing and S’mores and someone asked, “Would you like to see if we can find a moonbow?” I thought perhaps my more outdoorsy friends were playing a joke or, because this was back in my single days, I thought maybe this one guy was doing the Yosemite equivalent of “Come look at my etchings.”

So, first I needed to know, “What’s a moonbow?” I was enchanted to learn that it is a rainbow caused by moonlight and waterfalls rather than sunlight and rainfall. I grabbed a flashlight, and four of us headed into the dark, while the less intrepid stayed with the kids in the group who were already snuggled into their sleeping bags.

Yosemite is one of the few places in the world where people can actually see a moonbow. Victoria Falls in Africa and Waimea in Hawaii also offer this rare feat of nature, but when the conditions are right, Yosemite does it near Half Dome!

My curiosity was as bright as the full moon over the pines.

Driving and hiking from waterfall to waterfall in the clear night air was its own reward. But at last, at the base of Yosemite Falls about 2 a.m., we saw a small reverential crowd. An arc of ephemeral, opalescent light and bands of pastels appeared and disappeared in the cascading drops. I have since learned that sometimes moonbows are as boldly colored as rainbows; other times they are ghostly albinos.

Our night, it looked like a lightshow for fairies. And one more “Awe” was added to my list of Yosemite wonders.