Night Rainbows by the Light of the Moon

Upper Yosemite Falls Moonbow, originally uploaded by Jeff Sullivan (Truckee today).

You may not have ever thought about it, but the sunlight reflecting off of the full moon is actually bright enough to create rainbows at night! This phenomenon is easiest to see in the mist of waterfalls, when the angle between the moon’s light and your position is just right.

Fortunately if you’d like to know when they’re most likely to be visible in Yosemite Valley, Don Olson of the Department of Physics at Texas State University has made it easy for you, publishing predictions for Upper Yosemite Fall and Lower Yosemite Fall.

Lower Yosemite Fall from Cook’s Meadow.

Moonbow reflected in a vernal pool in Cook’s Meadow.

From the short hiking path to the base of Lower Yosemite Fall.