Wikipedia describes rogue waves as follows. “Rogue waves (also known as freak waves, monster waves, killer waves, and extreme waves) are relatively large and spontaneous ocean surface waves that are a threat even to large ships and ocean liners. In oceanography, they are more precisely defined as waves whose height is more than twice the significant wave height (SWH), which is itself defined as the mean of the largest third of waves in a wave record. Therefore rogue waves are not necessarily the biggest waves found at sea; they are, rather, surprisingly large waves for a given sea state. “Rogue waves are not tsunamis, which are set in motion by earthquakes [and] travel at high speed, building up as they approach the shore. Rogue waves seem to occur in deep water or where a number of physical factors such as strong winds and fast currents converge. This may have a focusing effect, which can cause a number of waves to join together.”

We have rare video of rogue waves here or below.

According to The Australian, “two huge waves have dragged dozens of people from a sea wall to a rocky beach hosting the world’s richest big-wave surf contest, leaving some with broken bones.

A total of 13 spectators at Mavericks Surf Contest in California had significant injuries, including broken legs and hands, California Department of Forestry and Fire Protection battalion chief Scott Jalbert said yesterday. At least three were taken to hospital.

Mr Jalbert estimated “a couple (of) hundred” people were on the seawall at the southern tip of Mavericks Beach when the waves struck, upstaging the competition that draws some of the world’s top surfers for a $US150,000 ($169,000) prize.

“Nobody was swept away into the water. They were just swept on to the beach area pretty hard,” he said. “It’s pretty rocky.

“We were very lucky that nobody was swept out to sea.”

The surfing contest is held only when conditions are right. It got the go-ahead when forecasts predicted record-breaking waves, despite warnings that strong winds could make the breakers dangerously unpredictable.

The waves knocked out barricades, a spectator platform and a large scaffold holding speakers broadcasting the contest, held in the harbour town 40km south of San Francisco. “