A rookie Coast Guard rescue swimmer saved a man's life just after a giant wave rolled the yacht he was piloting and threw him into the surf.
Video from a Coast Guard helicopter captured part of the dramatic save at the mouth of the Columbia River between Oregon and Washington state.
Petty Officer Michael Clark says the agency received a mayday call at about 10 a.m., with no additional information.
The agency was able to triangulate roughly where the call was coming from, and Coast Guard crews on vessels and in a helicopter who happened to be training nearby responded.
They found the 35-feet (11-meter) yacht, the P/C Sandpiper, taking on water in 20-foot (6-meter) seas - meaning the height of a wave from the previous trough could be as much as 40 feet (12 meters), Clark said.
The rescue swimmer - who was on his first rescue just after graduating from the Coast Guard's rescue swimmer program - was lowered from the helicopter by a cable.
As he neared the vessel, the man on board climbed onto the stern, preparing to get into the water.
But just then a huge wave slammed the boat, throwing him into the surf.
The wave struck so violently that the pricey vessel - which can cost more than £1200 per day to rent - rolled completely over and wound up floating upright.
The swimmer managed to locate the man in the surf and pulled him to safety aboard the MH-60 Jayhawk helicopter.
The crew brought him to Coast Guard Base Astoria, where medics treated him for mild hypothermia.
"It's a bit of a christening for a new rescue swimmer," Clark said.
The swimmer's name was not immediately released, nor was that of the man who was rescued.
The mouth of the Columbia, the largest North American river that flows into the Pacific Ocean, has such notoriously rough seas that it is known as "the graveyard of the Pacific."
In another story of survival in December, a man who fell off a cruise ship shared how he fought off a shark and ate bamboo for 20 hours to stay alive.
James Michael Grimes had no clue how he ended up in the sea but insists he wasn't drunk despite celebrating winning an air guitar competition on the vessel.
The 28-year-old says he treaded water and ate bamboo after he plunged into the water while on a Thanksgiving cruise with 18 members of his family last month.
In an interview with Good Morning America, he said he didn't have 'tonnes' of booze but 'couldn't really say' how much he consumed.
Sceptics now question his version of events, particularly how he could not know how he went overboard and how much alcohol he'd consumed before the incident.
Grimes thinks he fell overboard knocked him unconscious before he came to his senses in the water with no sign of the ship nearby.
He was rescued by the Coast Guard on November 24.
James had been spending Thanksgiving on the five-day cruise with 18 members of his family, including his parents and sister - as the ship travelled towards Cozumel, Mexico.
