Experts from Norway’s Accident Investigations Board are reviewing how a cruise ship carrying more than 1,000 passengers ended up in the North Atlantic during a significant storm.

Last weekend, the Viking Ocean Cruise’s Viking Sky suffered a serious propulsion malfunction during exceptionally rough seas. The ship’s captain issued a mayday call on Saturday, as he feared the vessel might have capsized or been blown into the shallows.

A massive rescue operation began shortly after the mayday call. The Norwegian Coast Guard dispatched helicopters to hoist passengers from the deck of the ship, which had anchored off of Hustadvika Bay in Norway about half a mile from shore, according to a report from the Associated Press (AP). During the rescue, the ship was bombarded by large swells, and passengers inside reported the vessel took moderate damage in the storm, with many windows blown out.

“When the windows and door flew open and two meters [six feet] of water swept people and tables 20–to–30 feet, that was the breaker. I said to myself, ‘This is it,’” said Rodney Horgen, an American citizen traveling aboard the Viking Sky, while speaking to AP reporters. “I grabbed my wife but I couldn’t hold on. And she was thrown across the room. And then she got thrown back again by the wave coming back.”

Other passengers posted pictures and videos of the incident on social media.