If you want to truly witness something unique — something that few people ever get to experience — you need to make a trip to see a moonbow. And, for those of us who lives in the Cumberlands, there isn’t much of a drive required to find one, because they occur right here in our back yard.
Cumberland Falls is one of the few places in the world where a moonbow can be seen. Moonbows are, as the name suggests, rainbows that are caused by the moon instead of the sun. They’re much rarer than rainbows because the weather and astronomical conditions have to be just right for them to appear, and they can only be seen at night.
The adventurer John Muir described the moonbow at Yosemite Falls like this: ” “Lunar rainbows or spray-bows abound in the glorious affluence of dashing, rejoicing, hurrahing, enthusiastic spring floods, their colors are distinct as those of the sun and regularly and obviously banded, though less vivid. Fine specimens may be found any night at the foot of the Upper Yosemite Fall, glowing gloriously amid the gloomy shadows and thundering waters, whenever there is plenty of moonlight and spray.”
But Yosemite isn’t the only place in the world to find a moonbow. You can also find them at Victoria Falls in Zimbabwe, Waimea Canyon in Hawaii, Skogafoss Waterfall in Iceland, Wallaman Falls in Australia and in Jerome, Ariz.
And, of course, Cumberland Falls. The eastern Kentucky waterfall is the only place in the eastern United States where a moonbow can be found. (In fact, Cumberland Falls is the only place in the western hemisphere where a moonbow can be seen regularly!)
What causes a moonbow?
Moonbows are caused by the mist from waterfalls reflecting the light of a full moon. That’s the simplest explanation, but there’s actually quite a lot that goes into it — which is why they aren’t seen just anywhere.
Moonbows only appear when the moon is full or almost full — usually two days before and two days after the full moon. That means there are only a few times each year that they can be witnessed, but the weather can foul things up. In order for a moonbow to appear, the sky must be clear, the wind must cooperate, and there can’t be any other bright light source present.
What does a moonbow look like?
To the naked eye, a moonbow looks like an arch of white light. You can see the shape of the bow, but — unlike rainbows — the colors aren’t bright enough for our eyes to see. Capturing the full wonder of a moonbow requires the magic of photography. Using a long exposure — which requires a tripod and remote shutter release — photographers are able to fully capture the magic of the moonbow’s array of colors.
Viewing the Cumberland Falls moonbow
Cumberland Falls is spectacular even in the ordinary daylight — which is why it’s often referred to as the Niagra Falls of the South. It is 125 ft. wide and seven stories tall. But on certain nights of the year, when the moon is full, Cumberland Falls becomes even more spectacular.
There is an 11-mile hiking trail at Cumberland Falls called the Moonbow Trail. It’s part of the Sheltowee Trace National Recreation Trail that ends at Honey Creek Trailhead in the Big South Fork National River & Recreation Area. It’s a challenging trail, intended for serious hikers. Fortunately, you don’t have to hike all 11 miles to see the moonbow. There are observation decks that are a short stroll from the parking lot.
The moonbow is usually visible a couple of hours after sunset.
Here are the remaining dates and approximate times to see a Cumberland Falls moonbow in 2021. Remember, the weather has to cooperate; if it’s cloudy or rainy, you aren’t going to see the moonbow.
March: 26th (7:30 p.m. – 9:30 p.m.), 27th (8:30 p.m. – 10:30 p.m.), 28th (10 p.m. – 12 a.m.), 29th (11 p.m. – 1 a.m.), 30th (12:30 a.m. – 2:30 a.m.).
April: 24th (7:30 p.m. – 9:30 p.m.), 25th (8:30 p.m. – 10:30 p.m.), 26th (10 p.m. – 12 a.m.), 27th (11:30 p.m. – 1:30 a.m.), 28th (12:30 a.m. – 2:30 p.m.).
May: 24th (9 p.m. – 11 p.m.), 25th (10 p.m. – 12 a.m.), 26th (11:30 p.m. – 1:30 a.m.), 27th (12:30 a.m. – 2:30 a.m.), 28th (1:30 a.m. – 3:30 a.m.)
June: 22nd (9 p.m. – 11 p.m.), 23rd (10 p.m. – 12 a.m.), 24th (11:30 p.m. – 1:30 a.m.), 25th (12:30 a.m. – 2:30 a.m.), 26th (1:30 a.m. – 3:30 a.m.).
July: 21st (9 p.m. – 11 p.m.), 22nd (10 p.m. – 12 a.m.), 23rd (11 p.m. – 1 a.m.), 24th (12 a.m. – 2 a.m.), 25th (12:30 a.m. – 2:30 a.m.).
August: 20th (9:30 p.m. – 11:30 p.m.), 21st (10:30 p.m. – 12:30 a.m.), 22nd (11 p.m. – 1 a.m.), 23rd (11:30 p.m. – 1:30 a.m.), 24th (12 a.m. – 2 a.m.).
September: 18th (9 p.m. – 11 p.m.), 19th (9:30 p.m. – 11:30 p.m.), 20th (10 p.m. – 12 a.m.), 21st (10:30 p.m. – 12:30 a.m.), 22nd (11 p.m. – 1 p.m.).
October: 18th (8 p.m. – 10 p.m.), 19th (8:30 p.m. – 10:30 p.m.), 20th (9 p.m. – 11 p.m.), 21st (9:30 p.m. – 11:30 p.m.), 22nd (10 p.m. – 12 a.m.).
November: 17th (6:30 p.m. – 8:30 p.m.), 18th (7 p.m. – 9 p.m.), 19th (7:30 p.m. – 9:30 p.m.), 20th (8 p.m. – 10 p.m.), 21st (9 p.m. – 11 p.m.).
December: 16th (6 p.m. – 8 p.m.), 17th (6:30 p.m. – 8:30 p.m.), 18th (7 p.m. – 9 p.m.), 19th (7:30 p.m. – 9:30 p.m.), 20th (8:30 p.m. – 10:30 p.m.).