3.2
Did the Norwegian Dawn encounter a rogue wave during its voyage on April 16, 2005?
Lee E. Branscome, Climatological Consulting Corporation, Palm Beach Gardens, FL; and M. N. Campbell
The cruise ship Norwegian Dawn (ND) suffered damage during the last leg of a regularly scheduled cruise on April 16, 2005. The ND left Miami at approximately 1 AM Friday April 15, 2005 and was scheduled to arrive in New York around midnight Sunday April 17, 2005. The ND encountered heavy weather and seas about 120 miles off the South Carolina coast on Saturday April 16, 2005. The deck log indicates that a very large wave hit the bow of the vessel, causing “heavy green seas” to cascade over the bow and strike the forward part of the ship's superstructure. Two of the forward cabins, on Decks 9 & 10 sustained major damage, 61 other cabins had water damage and 4 passengers required medical attention.
The representatives of the cruise line contacted a meteorological consulting firm with CCMs to determine if the ND encountered conditions that exceeded the NWS forecasts and if a rogue wave struck the ship.
The synoptic weather conditions indicated that a strong pressure gradient between a relatively weak low and a strong high pressure system over the North Atlantic Ocean was the cause of the heavy weather. The combined persistence and intensity of the winds and seas was unusual for the time of year and location where the ND encountered the heavy weather. Based on NWS forecasts the ship could have expected to encounter no worse than 45-knot winds (Beaufort Force 9 or strong gale) and seas of 24 feet along its planned route. Throughout its voyage, the ship remained at least 100 nautical miles west of any area in which the winds were expected to reach storm force (Beaufort Force 10) with seas up to 27 feet.
During the incident time, the ND's deck log indicated that the ship encountered winds of 34-47 knots and seas in the range of 30 – 46 feet. Seas of this height were not predicted by the NWS for the route of the ship, even accounting for the possible effect of the Gulf Stream. Independent data from other ships, buoys, satellites, and NOAA wind and wave hindcasts did not entirely concur with the deck log reports and indicated that the winds during the heaviest weather along the route were at most at the low end of the aforementioned range, and seas were probably no more than 27 feet. The wave that caused the damage on Decks 9 & 10 very likely exceeded the significant wave height by a large margin.
Session 3, The Role of the CCM in Severe Weather
Wednesday, 23 January 2008, 11:00 AM-12:00 PM, R04
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