Rogue waves, also sometimes called freak waves or killer waves, have long been mentioned in nautical folklore, but they have only recently been accepted as real by the scientific community.

The National Ocean Service describes rogue waves (also called “extreme storm waves”) as unexpected and dangerous swells that are more than twice the size of surrounding waves. They are unpredictable and can come from directions other than the prevailing wind and other waves.

Rogue waves can form through constructive interference, which occurs when waves moving at different speeds and directions across the ocean pass through each other such that their crests, troughs and lengths reinforce each other.

Weather in your inbox

Forecast Location

Sign Up

By signing up you agree to the Terms & Privacy Policy. Unsubscribe at any time.

Another rogue-wave-producing mechanism occurs when waves formed by a storm develop in a current against the normal direction of the waves, leading to a complex interaction that can result in waves dynamically joining together into a large rogue wave.

Senior writer Chris DeWeese edits Morning Brief, The Weather Channel’s newsletter.