hole-punch cloudsThree nearly identical, UFO-like cloud formations recently appeared over Myrtle Beach, South Carolina, sparking online discussions linking the features to everything from the Second Coming to recent mass bird deaths to secret military experiments.  Photograph P. Tyler

At least one scientist believes the so-called hole-punch clouds have a military explanation, though it may not be quite what conspiracy theorists expect.

Hole-punch clouds are miniature snowstorms that can occur in thin, subfreezing cloud layers.