Case Study :

The 'Great Storm' (SE England - October 1987)

The so-called "Great Storm" was the worst to affect south-east England for 290 years. It began in the Bay of Biscay off the north coast of Spain. At first meteorologists thought it was a typical depression caused by contact between very warm air from Africa and cold air from the North Atlantic. However, at about 6.00pm on 15 October 1987, it unexpectedly deepened giving a central pressure reading of 958 millibars.

It is still unknown why this happened but it may have been the result of extreme warming over the sea. It was the deepening combined with the change of direction from the English Channel towards the Midlands which caught experts by surprise. It developed so quickly that its severity was not predicted in advance weather forecasts.

The depression crossed the coast in south Devon soon after midnight. It then moved quickly towards the Midlands, deepening all the time and by half past midnight on 16 October, radio weather forecasts were warning of gales. An hour later the police and fire services were preparing to respond to emergencies caused by the extreme winds.

During the hours between 0300 and 0700 gusts of up to 166 km per hour were reported at Herstmonceux in East Sussex, St Catherines point on the Isle of Wight and in the Channel Islands. By 0500 winds were measured at 94 km per hour at Heathrow and over 100 km per hour on parts of the south coast.

By 0700 the centre of the depression had moved out to sea over the Humber estuary and the clearing up could begin.

Although the storm passed within a few hours, and during the night when most people were asleep, it left a trail of death and destruction. There were 16 deaths, several houses had collapsed and many others lost walls, windows and roofs. Thousands of trees were blown over blocking railways and roads and making it impossible for many commuters to reach London the next day. A ferry was blown ashore at Folkestone. Power and telephone lines were cut, and in some of the more isolated regions, they were not reconnected for several days.

In England in general, more than 15 million trees were lost, including some of the best known specimens. Sevenoaks in Kent lost six of the trees that gave the town its name. The cost in financial terms was enormous.

Storms of this magnitude can now normally be predicted in advance. However, the unexpected movements of this storm caught even the meteorologists by surprise, showing that you can never trust the weather.