Bizarre cloud over AZ
© Twitter/Madalyn Heimann
A bizarre cloud formation over western Arizona Monday night had locals in Phoenix and Yuma pondering whether there was a rocket launch out of California's nearby Vandenberg Air Force Base or maybe even a visit from some rainbow friends.

However, there were no rocket launches scheduled to take place at the base Monday night, so it is most likely to be a curious cloud phenomenon, KVOA reported.

According to some viewers, the formation looked like cloud iridescence, which occurs when tiny water droplets or ice crystals in clouds diffract light producing beautiful rainbow colors in clouds.

Others noted the possibility of noctilucent clouds, which are clouds in the upper atmosphere made up ice crystals that are only visible in a deep twilight.

Such clouds are usually seen in late spring and summer when the sun is below the horizon for the viewer but the high clouds are still in sunlight.

Local media reached out to the National Weather Service for a good explanation for the strange cloud formation that turned heads. However, officials were unable to give an official confirmation of what the "cloud" really is.