On the Job

Should Captains Be Concerned about Rogue Waves?

17 May 2023 By Kate Lardy
Credit: RichardALock/iStock

Based in Fort Lauderdale, freelance writer Kate Lardy got her start in the yachting industry working as crew. She spent five years cruising the Bahamas, Caribbean, New England, and Central America, then segued that experience into a career in marine journalism, which has included stints as editor of Dockwalk and ShowBoats International.

On November 29, 2022, the 202-meter cruise ship Viking Polaris was en route to Ushuaia, Argentina, in the turbulent waters of the Drake Passage, carrying 378 passengers, when out of the blue at 10:40 p.m. it was struck by what Viking Cruises declared in a statement to be a rogue wave. The anomalous wall of water smashed into the ships port side, breaking a string of cabin windows on passenger deck two. All over the ship, crew and passengers felt the jarring impact. As the icy sea rushed through the compromised windows, it uprooted furniture in the cabins, and in some cases pushed it up against the doors, pinning the occupants inside. Four passengers were injured, and, far worse, one passenger died from injuries caused by the shattered glass.

As in this real-life worst-case incident, which hit the headlines at press time, history has shown us that rogue waves can break ship windows and have the potential to crack hulls, but how common are they and should superyacht captains be concerned?

“Large, unexpected, and dangerous” — as NOAA puts it — rogue waves have gone by various unnerving names over the years, such as monster, killer, and freak. Generally defined by scientists as being greater than twice the height of the surrounding seas, they are an unfortunate result of colliding wave sets or swells interacting with currents. They are “very unpredictable, and often come unexpectedly from directions other than prevailing wind and waves,” according to NOAA.

“While fatalities are rare, and occurrences of rogue waves are relatively rare, both do happen and obviously are of concern for both yachts and commercial vessels.”

The Discovery Channel captured dramatic footage of this unpredictability when filming the TV series Deadliest Catch on the fishing vessel Aleutian Ballad. As the captain navigated directly into the heavy seas, an estimated 18-meter wave came out of nowhere to starboard, knocking the 33-meter boat flat on its port side and disabling both engines.

Documented examples span the world from Cape Horn — where in 2001, in two separate incidents, rogue waves shattered the bridge windows of two ships, leaving one adrift without navigation or propulsion — to the North Atlantic, and the Queen Elizabeth 2’s infamous 1995 encounter with a 29-meter mega-wave spawned from Hurricane Luis. One of the most tragic outcomes of a rogue wave occurred on the inland waters of the Great Lakes in 1975 when the 222-meter freighter Edmund Fitzgerald sank with all 29 crew on board lost.

The only good news? “They’re relatively infrequent occurrences,” says David Cannon, meteorologist and director of yacht operations at Weather Routing Inc (WRI). The worst part about them is their very sudden development. Unlike tsunamis, which are a displacement of water from earthquakes, rogue waves are the product of weather features that can churn up these waves seemingly randomly.

“The phenomenon is still undergoing a good amount of research in pinpointing a clear and common cause of rogue waves,” Cannon says. “Causes are mainly focused on high winds and currents and the interaction between wave sets, where waves will merge and actually take energy from different wave sets and form an exceptionally large wave.” 

In 2016, researchers at MIT developed an early-warning system for rogue waves, using an algorithm that can predict when a cluster of waves has a high potential to go rogue. But this system, which requires radar and lidar, only gives ships and offshore platforms a two- to three-minute window to prepare.

The greatest threat lies in the open ocean, says Cannon, “like in the North Atlantic, where you’re dealing with more progressive weather patterns. You have a gale track, a storm track, fronts, and high-pressure ridges. One notable area where rogue waves can be of concern is in the South Atlantic where there’s more wavecurrent interaction. For example, off the south coast of Africa, you have the Agulhas Current, which can run up against typically westerly wind and wave sets, and currents down that way can run as high as about four or five knots.”

He points out that if you’re cruising in one of these high-risk areas, you should always be on high alert, because the very nature of the weather features that are typically responsible for rogue waves — like large storms or tropical systems — is concerning enough. “There should always be the mindset that yachtsmen should be careful of just large waves, just because of the area they might be traveling in, the weather pattern that might be coming into play, and things like that.”

When we spoke with Cannon at WRI, he was finishing up a season of directing superyachts on a safe route from the Mediterranean to the Caribbean — a passage where yachts are less likely to encounter a rogue wave, he says. “It’s really in more northern latitudes where you have a greater potential for different wave sets colliding with one another, and the wave and current interaction.”

This article originally ran in the Janaury 2023 issue of Dockwalk.

 

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