Hawaiian surfers Garrett McNamara, down, and Kealli Mamala surf off the coast of Nazare, Portugal, January 29.
McNamara is seen riding the enormous cascading wave before falling to the sea.
His feat is thought to have set the new world record for tallest wave surfed. If that proves to be the case, McNamara will have broken the previously existing record, set by him, of 78 feet, which he did at the same location in November 2011.
Guinness World Records officials will being their verification process of the wave shortly.