The Voyager storm in the Mediterranean Sea

Ocean Engineering, 2008

We analyse the wind and wave conditions present in the Mediterranean Sea at the time and location when the cruise ship Voyager was reportedly hit by one or more big waves and suffered substantial damage. The analysis is done using wind and wave modelling supported by satellite and buoy wind and wave data. Granted the hindcast of the storm, we also analyse the local conditions for the possibility of freak waves. r

Description of freak waves is not only important for design work but also for operational purposes it would be of benefit if warnings could be given to mariners. Meteo-centers already provide wave forecast based on spectral wave model. Although a spectrum gives some average description of the sea-state, it might contain additional information indicating an increased probability of occurrence of exceptional waves. To this end a database with 650 ship accidents was extracted from Lloyd's Marine Information Service database. Their study may help in identifying the ocean areas more prone to bad weather in general and abnormal waves in particular.

mccip.org.uk

There is a history of strong variability in UK wave climate. Inter-annual variability in the modern wave climate is strongest in the winter and can be related to atmospheric modes of variability, most notably the North Atlantic Oscillation. Rather dramatic increases in wave height occurred between 1960 and 1990, but these are now seen as just one feature within a longer history of variability. There is no clear pattern in results since 1990. Natural variability in wave climate is strong and the role of anthropogenic forcing is uncertain. Previous projections of a strengthening storm track (for example featured in the latest IPCC assessment report) have been contradicted by the projections from UKCP09. These latest projections are for a southward displacement of the storm track, resulting in lower wave heights to the north of the UK and slightly greater wave heights in some southern regions. There is however no consensus on the future storm and wave climate, stemming from diverse projections of future storm track behaviour.

2010

We present a stochastic model of sea storms for describing long-term statistics of extreme wave events. The formulation generalizes Boccotti's equivalent triangular storm model (Boccotti 2000) by describing an actual storm history in the form of a generic power law. The latter permits the derivation of analytical solutions for the return periods of extreme wave events and associated statistical properties. Finally, we assess the relative validity of the new model and its predictions by analyzing wave measurements retrieved from two NOAA-NODC buoys in the Atlantic and Pacific Oceans.

Natural Hazards and Earth System Science, 2008

On 14 February 2005 a severe mistral storm caused substantial damage to the passenger cruiser "Voyager" between Balearic Islands and Sardinia. The storm had been well predicted. However, the ship was hit by one or more, apparently unexpected, large waves. Our aim was to understand if this was a freak event or it was within the expectable probability. At this aim we use our best estimate of the local wave conditions, obtained combining modelling and measured data. Starting from these we derive the probability of large waves, considering both linear and non-linear cases. Notwithstanding a correction towards the worse of the, otherwise inconsistent, available reports, on the basis of the data at disposal we conclude that, given the local conditions, the event was within the range of the potentially expectable wave heights. This turns out to be even more the case on the basis of recent results based on theoretical and experimental data.

2015

The Britta storm of 31 October-1 November 2006 was a severe autumn storm that was particularly damaging for shipping and coastal flooding from storm surge effects along the southern North Sea. The main low pressure of the storm propagated from Scotland to southern Norway on 31 October, leading to a system of strong north winds that moved southward across North Sea over an 18 h period. A progression of ship and offshore platform difficulties were registered from the northern part of the North Sea from late on 31 October and culminated near the coasts of Germany and the Netherlands early on 1 November with a series of ship emergencies linked with large waves. In two separate incidents, unusually high waves broke the bridge windows of ships and necessitated emergency rescues, and a Dutch motor lifeboat experienced a triple capsize. In the southern North Sea, several gas production and research platforms experienced wave impact damage. The FINO1 offshore research platform, near the Dutch-German border, experienced some of the worst storm conditions with some structural damage. Its meteorological and oceanographic instrumentation give a unique profile of the severe met-ocean conditions during the storm. Two Waverider buoys at FINO1 and the nearby Dutch coastal site of Schiermonnikoog recorded groups of large waves at different times during the storm. These reports give insight into a little-reported rogue wave phenomenon that sometimes accompanies the "ground sea" conditions of the worst storms of the area.

Physics and Chemistry of the Earth, Parts A/B/C, 2009

is a small town hidden in a bay on Korčula Island in the Adriatic Sea. In the early morning of 21 June 1978, the sea suddenly began to rise in the town, overtopping the piers and surging into the streets. The rumble of the incoming water awakened inhabitants who witnessed a series of destructive ocean waves, flooding much of the city and causing devastation and widespread damage. Tsunami-like waves with trough-to-crest heights of up to 6 m and periods of about 18 min appeared without any warning, resulting in the greatest natural disaster in the modern history of Vela Luka. Subsequent scientific investigations indicated that the waves were not related to a seismic event or submarine landslide but to atmospheric processes, identifying this as a meteorological tsunami event (Hodžić , 1979/1980; Orlić , 1980). Tsunamis are the main cause of destructive seiches observed in the World Ocean. However, long waves generated by atmospheric forcing (atmospheric gravity waves, pressure jumps, frontal passages, and squalls) can also be responsible for significant, even devastating, long waves which have the same temporal and spatial scales as typical tsunami waves. These waves are similar to ordinary tsunami waves and can affect coasts in a similar way, although their catastrophic effects are normally observed only in a limited number of specific bays and inlets. Nomitsu (1935), Defant (1961) and Rabinovich and Monserrat (1996, 1998) suggested the term 'meteorological tsunamis' ('meteotsunamis') for such waves. At certain places in the World Ocean, hazardous atmospherically-induced waves occur regularly and have specific local names: 'rissaga' in the Balearic Islands, 'marubbio' ('marrobio') in Sicily, 'šćiga' on the Croatian coast of the East Adriatic, 'milghuba' in Malta, 'abiki' and 'yota' in Japan, 'Seebär' in the Baltic Sea, 'death waves' in Western Ireland, and 'inchas' and 'lavadiads' in the Azores and Madeira islands. These waves have also been documented for the Yellow and Aegean seas, the Great Lakes, the northwestern Atlantic, for coastal areas of Argentina and New Zealand, and in some specific ports such as Port Rotterdam (cf.

Journal of Geophysical Research, 1978

The surface of the sea is usually a complex and irregular function of space and time, best described by statistical measures. Suerdrup and Munk [947] thus decided that the energy of the sea state was the proper quantity to be predicted by their significant wave method of hindcasting. Pierson [1952] greatly improved upon that idea by showing the practicality of hindcasting the directional spectrum, that is, the partition of the energy into various frequency and direction bands. The development of the directional spectral hindcasting method for hurricanes has been described by Cardone et al. [1976].

Coastal Engineering 1990, 1991

We discuss the application of the third generation WAM wave model to the Adriatic Sea. We focus in particular on one of the extreme storms that produced also heavy flooding in Venice. We discuss the problem of a correct description of the wind fields as a crucial input information to the wave model. After hindcasting the wave conditions during the storm, we use them as input for an estimate of the wave setup towards the shore. We show that its consideration is essential for a proper evaluation of the flood level in the town.