A question of surf: How do you measure a 100ft wave?

Professional surfer Garrett McNamara, may have broken his own world record for the largest wave ever surfed, after he caught one that reportedly measured 100ft in Portugal.

But there has been some debate about the actual size of the wave.

In 2011, McNamara broke the Guinness World record for catching a 78ft wave but it was initially thought to be "90ft".

So how do you measure the size of wave?

There is no exact science to wave, but according to the Billabong XXL Global Big Wave Awards judging committee - who authenticated McNamara's last record - it involves 'painstakingly' analysing and measuring photographs and video images.

After gaining an approximate objective measurement of the height of the wave and taking into consideration the angle of the photo or video and the height of the surfer, the ride is given an Estimated Face Height in feet.

The measurement panel then aim to come to an unanimous consensus.

*See also: *

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World Record for riding '78 ft wave'