Washington's Coast
Washington State Department of Ecology

big waves
rip currents
sneaker waves
Sneaker wave or large, unexpected wave
Sneaker wave warning, North Jetty, Columbia River Unpredictable high waves
High waves can hit, even on calm days. Don't turn your back on surf. Avoid logs.
What is a sneaker wave?
Sneaker waves are large, unexpected waves. Sneaker waves rush up on the beach, catching people off guard -- even on dry land. They can be dangerous, especially for children.
  • Higher and stronger than normal surf
    Sneaker waves can run up on the beach as much as 100 yards.
  • Often occur during outgoing tides
    Sneaker waves occur daily and vary in size and intensity.
  • Not weather related
    Sneaker waves can strike on calm days or stormy days.
Can sneaker waves be predicted?
Sneaker waves are formed by a mix of waves. Big waves move faster than smaller ones. When big waves catch up with small waves, they grow faster and stronger. When waves will combine and hit a certain location is difficult to predict.
How to avoid sneaker waves
  • Never turn your back on the surf
    Be beach safety smart. Watch out for sneaker waves. Supervise children at all times.
  • Avoid logs and debris
    Sneaker waves are strong enough to take the biggest log and toss it on you. Stay away from logs in surf or wet sand. Do not sit or stand on logs. Keep children way from logs and large debris.
  • Avoid jetties
    Jetty rocks can be slippery from mist, rain, or spray. Large waves can knock people off a jetty and send them crashing into the rocks. Stay away from jetties, particularly during storms, high tide, or tidal changes.
High waves top the North Jetty, Grays Harbor, January, 1997.

Is every seventh wave the biggest?
"As I have traveled about, I have found every integer from three to nine enshrined in folklore. If you put your faith in any pet integer and have the temerity to prove your faith in a sailing dinghy, you will sooner rather than later be slapped silly by a wave numbered pet integer plus one. The answer is NO."
--- SB. Kinsman, oceanographer, West Coast Marine Weather Hazards
Manual, Environment Canada.



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