Storm Surges

Storm surges aren’t just a threat to the United Kingdom; they have a long history of occurring all over the world. Mainland Europe, the north coast of Australia, the east coast of the United States and parts of Asia all suffer from the extreme weather phenomena but the level of protection offered to different countries and cities varies considerably. Some have absolutely no protection against the threat, whilst others have multiple sophisticated defences. London has the Thames Barrier, but this alone cannot guarantee the safety of the city. Click the links to find out what would happen to East, Central and West London if the barriers were to be overwhelmed by a storm surge.

What is a Storm Surge?

In a nutshell, a storm surge is a large hump of water caused by low atmospheric pressure at sea. When strong winds act on these humps they can be pushed towards land and form what is commonly known as a tidal wave, or tidal surge. To find out more about the formation of storm surges and how they can affect London, click here.

The Netherlands

The Thames Barrier is the second largest movable flood barrier in the world, exceeded only by The Oosterscheldekering in the Netherlands, the largest of the country’s 13 flood defences, collectively known as The Delta Works. Like the Thames Barrier, their construction was in response to the storm surge of 1953, though they are far more comprehensive, providing North and South Holland with a 1 in 10,000 chance of being overwhelmed by a storm surge in any given year. That’s 10 times the level of protection that London receives.

The United States

The United States has spent much time in the media in recent years due to the effects of storm surges. As a country that is quite regularly affected by hurricanes, storm surges are a large threat.

In 2005 New Orleans was devastated by the storm surge that hit along with hurricane Katrina, flooding 80% of the city. This graphic reconstruction shows just how severely storm surges can affect a city without flood defences.

More recently, in August of 2011, the east coast of North America was threatened by a tidal surge caused by Hurricane Irene. New York City ordered its first ever mandatory evacuation of low-lying areas, evacuating 370,000 people. Shelters were set up in the city to provide protection from the flood, though there was only room for 70,000. Cities along the coast followed suit, evacuating the coastal and low-lying areas.

New York remained relatively unscathed, but North Carolina was amongst the worst hit areas. In Pamlico waters were reported at 13 feet above normal, whilst the Manteo Causeway was said to have been under 5 feet of water.

New York is especially vulnerable to storm surges as it is on the coast and has large areas of low-lying land mass. The south of the city is especially vulnerable to tidal surges as are parts of the north.

In November of 2010 it was reported that the city was considering plans for a storm surge barrier, to be included in the Vision 2020 plan, which aimed to revolutionise the city’s waterfront over a 10 year period. There was no specific plan laid down for barriers in Vision 2020’s press release, but it did say that it would promote research into storm surges.

Much of New York is just 3 metres above sea level, whilst 260 square kilometres are at risk from a 100-year flood. This means that in any given year, there is a 1 in 100 chance that the city will flood, making it 10 times more likely than a similar flood occurring in London and 100 times more likely than one in the Netherlands. When the results of global warming are considered, by 2090 the risk could be 1 in 30. In an absolute worst case scenario by 2020 it could be a 1 in 40 chance, by 2050 a 1 in 20 chance and by 2080 a 1 in 4 chance.

In 1992 the maximum sea level peaked at 8.5 feet above mean levels at Battery and, although only a foot or two of water descended on the city for a brief period of time, it caused chaos. The subway was completely shut down along with transport links to New Jersey.

This alone suggests that the effects of global warming need to be reduced. Some of the world’s major cities are already threatened with disaster on a yearly basis, without global warming contributing to the situation. As unlikely as such an event is, the risk is just too big to gamble with the lives of thousands of residents. Click here[hyperlink] to find out what you can do to reduce the effects of global warming.

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