It takes a certain moon phase, a certain angle of viewing and a clear night to see what’s been called the only moonbow in the Western Hemisphere.
By nature, it would seem odd to watch a waterfall at night—in the dark. But, way past 10 p.m., the parking lot was getting mighty full under a full moon in May at Cumberland Falls State Resort Park.
Couples strolled hand-in-hand on the lit, paved walkway. And all ages shared a collective hush as they stood—hundreds deep, in the dark—at the popular park’s upper overlook.
You would think—judging from this crowd—that the gushing, 68-foot-tall waterfall was most popular at night. Bret Smitley, a naturalist at the state park near Corbin, Kentucky, says it’s not so. Still, for nighttime viewers, Smitley says, “If the full moon falls on the weekend, that’s going to be your busiest time.”
That’s when as many as 2,000 come out to see the moonbow on clear nights. This lunar light appears as a white bow that arcs downstream. And it can be seen, Smitley says, so long as there’s plenty of mist spraying across what’s affectionately called the “Niagara of the South.”
“You know, a lot of waterfalls just don’t produce a lot of mist,” Smitley says. “The reason why we have it, in my opinion, is you’re able to stand between the water source and the light source. So you’re just standing in the correct angle where that light is being refracted off the mist. It’s accessibility, really.”
Park signs claim this is the only moonbow—besides Victoria Falls at Zimbabwe, Africa—that can be seen on a predicted schedule. A state historic marker claims, “The Moonbow that appears here is the only one in the Western Hemisphere.” Yet that may not be true, as other similar moonbows have been reported at Yosemite National Park in California.
Smitley, still, knows it’s a rarity.
