Phenomenon that brought disaster
Published: 11:16, 04 February 2003
THE 1953 floods were the result of a combination of factors causing a storm surge, a phenomenon that creates exceptionally high tides.
Tidal records show that the 1953 sea level was the highest since records began in 1911. The frequency of an event of that magnitude is estimated to occur only once in every 1,000 years.
Surges are caused mainly by the action of the wind on the surface of the sea, with barometric pressure as a secondary factor. They travel anti-clockwise around the North Sea basin and take about 24 hours to progress.
The 1953 storm also coincided with spring tides and high river discharges into the North Sea. Together they produced tides more than nine feet higher than normal along the north Kent coast.
Following the 1953 floods it was recommended that a flood-warning organisation be set up, and the Met Office responded by helping establish the Storm Tide Forecasting Service.
The service is based on sets of gauges that measure water levels in 10 coastal areas around England and Wales. If the sea level is forecast to reach or come close to pre-defined danger levels an alert is issued, typically 12 hours before the event.
This gives the authorities the time to close flood barriers and initiate emergency procedures. A Met Office spokesman said: "Since the 1953 floods, forecasting accuracy has increased exponentially. The first computer was installed nine years ago, followed by cutting edge upgrades over the years."
He added: "The events of 50 years ago show that severe weather is not a new phenomenon but as the frequency of severe weather events increases, the Met Office is increasingly well prepared to provide accurate advance warning. "Climate change is, however, increasing the number of occasions when such warnings may be necessary." According to the Met Office's Hadley Centre, which specialises in climate prediction, events expected once every 50 years will increase to once every three years by the 2080s. Rising sea levels will also increase risks, leading to larger storm surges.
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KentOnline reporter