Sneaker Waves

People intimately familiar with the ocean's movements - like lifeguards, surfers or oceanographers - might simply call them "set waves." Others just refer to them as "waves that are larger than others." But if you're pummeled by a sudden wave while carelessly strolling along the beach, the term "sneaker wave" might strike a chord.

Sneaker waves are extremely large ocean waves which appear suddenly and without any warning at all. Since sneaker waves are unexpected, they represent a serious hazard to both people and ship traffic. Some regions of the world are more prone to sneaker waves than others, leading to posted warnings and advisories to make visitors aware of the issue. Any ocean or large body of water has the potential to form sneaker waves, so people should always be cautious around water.

Sneaker waves form when several smaller waves combine their energy, creating a single big wave. This can happen as a result of the disruption of ocean currents, or because of subtle changes in weather and topography. They follow no known pattern, and they will interrupt the established wave pattern, so even if people think they know the water, they should be careful. Sneaker waves are very strong, and they can kill.

The height of a sneaker wave can be significantly higher than the waves which precede and follow it. Sneaker waves have been known to crest headlands, pulling down hikers and ocean-watchers. They can certainly yank someone from a beach or rock piling, and they can also carry debris which may cause serious injuries. On the open ocean, sneaker waves have swamped ships; even massive tanker ships are not immune to the dangers of freak waves.

So, when you are enjoying the beach, please take these precautions to avoid a disaster:

-Always keep a sharp eye on the ocean.

-Never turn your back on the ocean.

-Stay away from large drift wood. (especially in wet sand)

-Stay clear of rocks and cliffs.

-Always watch and be within reach of your children.

More Weather Glossary

  • Hoar Frost

    After a cold, clear winter night without much wind, the ground and nearby tree branches may be covered by tiny, white ice crystals.

Daily U.S. Extremes

past 24 hours

  Extreme Location
High N/A
Low N/A
Precip N/A

WeatherWhys®

This Day In Weather History

Omaha, NE (1975)
Massive tornado killed 3 people and injured 133 while causing 150 million dollars worth of damage. Tornado cut a swath 10 miles long and one-quarter of a mile wide through the industrial and residential areas of west-central Omaha before lifting over the northern section of the city. Most costly U.S. tornado to date.

Plains (1983)
Thunderstorms rake over Nebraska and Kansas with golf ball-sized hail, wind gusts close to 90 mph at Superior, NE, and 3-1/2 inches of rain at Kensaw, NE.

Sheridan Lake, ND (1984)
Lightning struck a boat out on the water, killing two occupants. A life vest was torn to bits by the powerful bolt.