Rogue waves have largely been dispelled as myths, fancy stories of men at sea, and exagerated accounts of life at sea, until recently.
Scientists have recently been able to determine how rogue waves are made and where they are most likely to take place. In the past, they were seen as unpredictable, but now through understanding of ocean currents it is much more easy to predict where and when a rogue wave might be encountered.
The primary specifications for a rouge wave are a combination of wind and sea current. When the water current in an area is flowing strongly in one direction, and strong wind currents flow in the opposite direction, the two collide. When they collide, the wind pushes against the water, forcing the water upwards, creating a higher than usual wave.
When the water current is strong and the wind is severe, the outcome can be huge waves. This type of rogue wave can normally be found off shore.
Rogue Waves
What Are Rogue Waves?
How Do Rogue Waves Form?
North of the equator currents bend to the right, south of the equator they bend to the left. This is called the Coriolis effect. Winds, continents and the Coriolis effect make currents flow around the oceans in huge loops called gyres.
During hurricane season around North America, it become obvious using the map above, that there is a stronger liklihood of rogue waves at this time, off the east coast of the U.S. from Hurricanes that formed in the Gulf Of Mexico, and moved north and northeast over the U.S. Water currents are flowing east to west in the Atlantic, and strong winds from tropical storms and hurricanes will be flowing from west to east.
Hurricanes move over North America with a spiral motion. The hurricane as a whole moves west to east ultimately, and the winds flowing out of the hurricane spiral clockwise, or hooking to the east.
You can see looking at the water currents above, that when a hurricane coming off North America into the Atlantic encounters those water currents, they are going to collide. There will be higher seas because of the winds within the tropical system and higher seas as the tropical winds collide with the water current.
Knowing how the water current flows in the path of a cruise, should make the prediction of possible rogue waves fairly easy, with satellite imagery to show the predicted wind currents that may collide with a strong opposite water current.
The question then becomes, do we take an evasive course, causing delays and affecting our earnings or do we take it as it comes, and see what happens? Of course, because there is no clear certainty that anything will happen, the cruise line is going to tell the ship to plow ahead, and see what happens.
Looking at the water current map above, you can see the water currents off the coast of North and South Carolina. This is where the Norwegian Dawn encountered a 70 foot high rogue wave on April 16, 2005. It should have been an expected event.
Marine Weather Review - Tropical Atlantic and Tropical East Pacific Areas January through May 2005
The incipient low pressure that produced this storm event developed over the central United States. The low then tracked east-southeastward across Kentucky and the Carolinas early on the 13th. Around 1800 UTC 13 April, it moved off the coast of North Carolina near Wilmington. Once offshore, the low quickly strengthened into a gale center then it became nearly stationary about 250 nmi southeast of Cape Hatteras. At this time, gales were occurring to the northwest and north of the low. By 0600 UTC 15 April, the low strengthened into a storm center and began to move slowly southeastward. At 1800 UTC, the 1004 hPa storm was centered near 33N 73W. At this time, gale force winds began in the Tropical Prediction Center's marine area. QuikSCAT data at 2344 UTC 15 April (Figure 2) indicated storm force winds off the coast of North Carolina with gale force winds extending south to about 29N.
As seen in the NOAA report above, the ship and cruise line should have anticipated this rough weather event as early as April 13, 2005, giving them a three day window of opportunity to avoid this situation.
However, Norwegian Cruise Lines had paid $1 Million to have the Norwegian Dawn seen on the popular television show The Apprentice, with the vessel needing to be back in New York harbor on April 16. So, the ship pressed on, inspite an sailing into obvious severe weather and seas.
Ships slammed by rogue waves:
Norwegian Dawn 70 Foot Wave - 04/16/05
Norwegian Spirit 50 Foot Wave - 01/19/06
Prinsendam - 40 Foot Wave - 02/01/07
QE2 95 Foot Wave - 09/11/95
