The mysterious vessel landed ashore amid a burst of violent, stormy weather, wedging itself onto a rocky outcropping and perplexing local residents and authorities. How could such a large ship have been marooned? Was anyone inside?

A jogger first noticed the 2,400-ton vessel Sunday, sitting below a seaside cliff on Ireland’s southern coast. Later that day, the Irish Coast Guard sent a rescue helicopter to the scene, hoping to make contact with any crew members who may have been aboard the ship.

As it turns out, the boat that had washed ashore near the city of Cork was known as a “ghost ship,” long floating around the Atlantic without anyone aboard. Since being abandoned by its crew nearly 17 months ago, the MV Alta had drifted alone across the ocean, rusting and breaking down as it skirted near Africa, Europe and the Americas.

“This is one in a million,” said John Tattan, an official with the local branch of the Royal National Lifeboat Institution, a nonprofit that rescues people stranded at sea off the British and Irish coasts. “I have never, ever seen anything abandoned like that before.”

Tattan said it was particularly bewildering that the Alta managed to make it past the many fishing boats off Ireland’s southern coast without being detected.

The government of County Cork warned the public to stay away from the location of the wreck, noting in a statement Monday that “it is located on a dangerous and inaccessible stretch of coastline and is in an unstable condition.”

Built in 1976, the MV Alta was sailing under the Tanzanian flag and had most recently changed ownership in 2017 – although it was not clear to whom. The cargo vessel was sailing from Greece to Haiti in September 2018 when it was disabled in the middle of the Atlantic Ocean, leaving 10 crew members stranded about 1,380 miles southeast of Bermuda. Unable to make repairs, they had to be airdropped a week’s supply of food as they waited for help.

Nearly 20 days later, a U.S. Coast Guard cutter arrived to rescue the crew and take them to Puerto Rico, according to gCaptain, a maritime industry news site. Coast Guard officials also reached out to the ship’s owner, hoping it might hire a commercial tugboat to tow the vessel to shore.

Whether that happened is unclear. Some said the Alta was hijacked while being towed to Guyana, perhaps even twice.

It was not officially spotted until almost a year later. In August 2019, an ice patrol ship manned by Britain’s royal navy came across the Alta in the middle of the ocean, making contact to offer help but receiving no response.

What happened after that encounter is equally mysterious. Tattan told the Examiner newspaper that he believes the Alta crossed the ocean toward Africa, where it drifted north past the Iberian Peninsula and into the Celtic Sea, just south of the British Isles.

Then, over the weekend, Storm Dennis caused widespread flooding and prompted evacuations across the British Isles. Dubbed a violent “bomb cyclone,” Dennis brought nearly a month’s normal rainfall in just 48 hours, gusts up to 70 mph and waves up to 80 feet tall.

And it seems to have brought the MV Alta, too.

The discovery of the marooned ship initially sparked County Cork’s contingency plan for potential oil spills, as officials monitored how fuel or any cargo aboard might affect the coast, known for its green hills, sandy coves and nearby conservation areas.

Officials determined Monday there was no sign of pollution. On Tuesday, they said, a contractor was expected to inspect the ship at low tide to determine what to do with it.