2011: costliest ever year for earthquakes, weather-related disasters

terms of their severity, however, the quakes were not as bad as the devastating event in February. Consequently, losses for the insurance industry from these aftershocks are expected to be significantly lower.

Professor Peter Höppe, head of Munich Re’s Geo Risks Research unit, said: “Even if it seems hard to believe given recent events, the probability of earthquakes has not increased. However, these severe earthquakes are timely reminders that the decisions on where to build towns need careful and serious consideration of these risks, especially where certain buildings are concerned, above all nuclear power plants. Also, building codes in regions exposed to earthquakes need to be made even stricter, so that buildings do not just remain standing to an extent sufficient to save lives but can be used again afterwards.”

Weather-related catastrophes: Floods in Thailand

Thailand’s floods
The floods in Thailand stand out among the many weather-related catastrophes of 2011. They were triggered by extreme rainfall, which started in spring and peaked in the autumn. Due to its low elevation above sea level, the plain of central Thailand — where the capital Bangkok is situated — is prone to flooding throughout the rainy season from May to October. According to the authorities, this year’s floods were the worst for around fifty years. It is presumed that the La Niña natural climate phenomenon was a contributory factor, since the rainy season is often stronger during this phase.

The floods claimed the lives of some 800 people. Not only were hundreds of thousands of houses and vast expanses of farmland flooded, but also seven major industrial areas with production facilities belonging mainly to Japanese groups. A large number of electronic key component manufacturers were affected, leading to production delays and disruptions at client businesses. Approximately 25 percent of the world’s supply of components for computer hard drives was directly impacted by the floods. With economic losses amounting to tens of billions of dollars, the floods were by far the costliest natural catastrophe in Thailand’s history.

North America: storms and hurricanes
The tornado season was especially violent in the Midwest and southern states of the United States. Several series of storms with numerous tornadoes caused economic losses totaling some $46 billion, of which $25 billion was insured. Insured losses were thus twice as high as in the previous record year of 2010. The series of severe weather events can largely be explained by the La Niña climate phenomenon. As part of this natural climate oscillation, weather fronts with cool air from the northwest more frequently move over the central states of the United States and meet humid warm air in the south. Under such conditions, extreme weather events are more probable than in normal years.

Losses from North-Atlantic hurricanes were moderate. As in 2010, however, this was purely by chance. At eighteen, the number of recorded tropical cyclones in this season was some way above the long-term average (eleven) and above the average for the current warm phase with increased hurricane activity since the mid-1990s (fifteen). The number of hurricane-strength storms (six) was in line with the long-term average. The number of tropical cyclones that made landfall, especially on the United States coast, was very low, however. Only three named storms, one of them Hurricane Irene, made landfall in the United States. Irene caused economic losses in the Caribbean and the United States totaling $15 billion, $7 billion of which was insured.

Another striking feature of this year was that, for the first time ever, U.S. weather agency NOAA categorized a low-pressure system over the Mediterranean as a tropical storm. The low-pressure system Rolf formed on 3 November. It was caused by a ridge of cold air forming over the still warm sea (20°C). With peak wind speeds of 120 km/h, the storm “01M” made landfall on the French Mediterranean coast before dispersing. The storm produced extreme rainfall along the Cote d’Azur.