A small business owner has explained why swimmers should never turn their backs on the ocean after he captured a terrifying video of a wave crashing into beachgoers in Hawaii.
California-based surfing expert Matt Moore was visiting a beach on the North Shore in Oahu, Hawaii, when he and other beach visitors witnessed three men slammed by a wave in a rocky area on November 29.
Two of the swimmers went underwater while another stood on rocks before the wave quickly rushed over the top of them.
The three swimmers slowly stood up after the wave passed, but they were pounded by a second wave less than 10 seconds after they made it out from under the water.
The two men closest to the wave were immediately submerged while the third managed to keep his head up and float away.
Both swimmers the wave hit the hardest did not come up from the water after the second wave, but the third person managed to make it through all four waves in the video.
Once the two swimmers disappeared into the water, an unidentified woman suggested she and Moore call for help.
All three swimmers were injured after the incident but they managed to make it out of the water alive.
A surfing expert captured footage of three swimmers being slammed by waves at a beach on the North Shore in Oahu, Hawaii, on November 29
Honolulu Ocean Safety shared the video on social media and confirmed the incident occurred between Sharks Cove and Ke Iki.
The government agency added that a beachgoer already called 911 while Moore was recording.
'The video speaks volumes to how dangerous it can be,' Honolulu Ocean Safety said regarding the large winter waves.
'Fortunately these three young men went home tonight but they were seriously cut up,' they added.
Moore posted another video regarding the Hawaiian beach incident yesterday and how he captured the footage on December 2.
'It was just a quick deal where we were filming and looking at waves, and I turned around and saw them,' Moore said.
'We caught the action of the big set come over their head and almost take them out... It's a good lesson for everybody that's visiting in Hawaii to be careful.'
The surfing expert noted that all three swimmers were locals and that he is glad to know they were okay.
Two of the swimmers closest to the waves remained underwater while the other stood on the rocks
The North Shore in Oahu, Hawaii, is a popular surfing destination in the winter, and it is known for producing powerful waves.
Waves in the Shore's light areas usually have two to four-foot waves in the summer and between six and eight-foot ones in the winter.
Advanced areas of the North Shore usually have waves around four to six feet in the summer but can be a whopping 30 to 50 feet in the winter.
The North Shore waves can also be extremely dangerous, and fatal incidents have occurred many times over the last few years.
Oklahoma resident Susie Jett lost her life last October after she was swept out to sea by a wave on Kei Iki Beach at the North Shore.
Jett's daughter Laura Rich and California resident Bryan C Kunic were also swept out to sea.
Rich recovered from her injuries, but Kunic was pronounced dead at the scene.
The late surfing legend Tamayo Perry died on the North Shore from a shark attack in June.
Perry, who appeared in Blue Crush and a Pirates of the Caribbean film, was found on Mālaekahana Beach missing an arm and a leg.
