Oceanography

What makes a rogue wave rogue and how do they form?
Answered by Planet Green
• ### Planet Green

1. Rogue waves are massive waves that appear out of nowhere. The height that classifies a wave as rogue isn't set in stone. Some experts call a wave rogue if it's twice as high as the other waves surrounding it. Others say that to be rogue a wave only needs be 33 percent taller than surrounding waves. Not only are rogue waves taller than other waves, they're also usually steeper. Sailors who encounter rogue waves often describe them as walls of water that slam into ships. They are probably more common than people originally thought. Over the course of six years in the 1990s, three big ships were hit by massive waves; until then, scientists thought rogue waves were only produced every 50 years. The European Space Agency used satellites to track rogue waves over the span of three weeks in 2004. Data showed 10 waves that measured a minimum of 82 feet (25 meters).

Scientists aren't sure how rogue waves form, but they have a few good hypotheses. One option is that currents in the ocean force waves to pile up when they hit. If a storm-size wave of 40 or 50 feet (12 or 15 meters) runs into a powerful current, the current can add to its size and force the wave to break, producing a massive 98-foot (30-meter) wave. It would explain the wall of water effect commonly associated with rogue waves. Another explanation for the source of rogue waves is random wave pileups. According to this theory, when two waves come together, wave reinforcement adds the waves' heights together. So that means if 8 five-foot-high waves come together at the same time, a 40-foot-wave could be produced in an otherwise calm sea.

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• ## Is there a point where we empty all of the ocean's resources?

### Answered by Daniel Pauly

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