On the night of 7 December 1703, the United Kingdom was visited by an extreme weather event.

Following weeks of wind and rain, a cyclone blew through the country at midnight, from the Welsh coasts to the Midlands and the south of England, hitting the cities of Bristol and London in particular. The storm also wreaked havoc in continental Europe, causing severe damage in the Netherlands, the Danish islands and Germany.

Remembered through history as the "Great Storm of 1703", it is a contender for the worst storm Britain has ever seen. Queen Anne described it as "a Calamity so Dreadful and Astonishing, that the like hath not been Seen or Felt, in the Memory of any Person Living in this Our Kingdom."

Just before the 1703 storm struck, the novelist Daniel Defoe noticed that the Mercury had "sunk lower than ever I had observ'd it" and assumed the instrument had been meddled with by his children. He recorded the "terrible night" in great detail in a 1704 book, The Storm, using accounts sent in from people across the country.

The Great Storm of 1987 is often said to be Britain's worst storm since the Great Storm of 1703. But was the 1703 storm the greatest in British history, prior to 1987?

The late Hubert Lamb, founder of the Climatic Research Unit at the University of East Anglia in Norwich, UK, studied the storm in collaboration with Knud Frydendahl of the Danish Meteorological Institute. In their 1991 book Historic Storms of the North Sea, British Isles and Northwest Europe, they ranked it just fifth in a chart of severity.

The storm scored 9,000 on their "severity index". This was based on wind speeds, area covered by damaging winds, duration of damaging winds, as well as total damage to landscape and property, and the number of human and animal lives lost.

A cow was blown into the high branches of a tree

The most severe storm according to Lamb's index was the storm of 1987 with a score of 20,000, followed by the storms of 1792 (12,000), 1825 (12,000) and 1694 (10,000, but with the caveat that this storm is poorly known because it happened so long ago).

So why has the Great Storm of 1703 remained in collective memory, more so than several others that were apparently more severe? Partly it is thanks to Defoe and his detailed and popular account, which turned the storm into Britain's first weather-related major news story.

It may also be because of the physical damage the storm caused. The impact was especially heavy because it hit the south of England, with its populated cities and busy harbours.

The storm uprooted thousands of trees; blew tiles from rooftops, which smashed windows in their paths; and flung ships from their moorings in the River Thames. A boat in Whitstable, Kent was blown 250m inland from the water's edge.

As Britain slept, the wind lifted and dropped chimney stacks, killing people in their beds. It blew fish out of the ponds and onto the banks in London's St James's Park, beat birds to the ground and swept farm animals away to their deaths. Oaks collapsed and pieces of timber, iron and lead blasted through the streets. The gales blew a man into the air and over a hedge. A cow was blown into the high branches of a tree. Lightning kindled fires in Whitehall and Greenwich. From the hours of five in the morning until half past six, the storm roared at its strongest. It is thought between 8,000 and 15,000 people in total were killed.

If you've got westerly winds in the Channel, you cannot sail down the Channel

Strong and persistent winds had already blown through the country for 14 days leading up to the storm. Those winds were already fierce enough to topple chimneys, destroy ships and blow tiles from the roofs of houses.

"In terms of its dramatic impact, it's up there with the best of them," says Dennis Wheeler, emeritus professor of climatology at the University of Sunderland. "Thousands of sailors died. The number was put at about 6,000. At the time, we were engaged with the War of the Spanish Succession, so we could ill afford to lose them. We lost a lot of ships, a lot of trade, and there was horrendous damage."

Records show the country experienced westerly winds in the weeks preceding the storm which meant ships were crowded in the English Channel, waiting to travel out.

"If you've got westerly winds in the Channel, you cannot sail down the Channel," says Wheeler, who studied the storm in 2003. "You've got all these ships waiting to sail out with goods."

Plenty of Royal Navy ships had amassed in the region too, he says, ready for an assault on the Spanish coastal city of Cádiz – an operation that ultimately ended with the forces taking Gibraltar instead. Thirteen Royal Navy ships and many merchant vessels were lost in the Channel, along with the sailors.

Modern meteorologists have studied the storm to find out what happened.

In his 1991 book co-written with Knud Frydendahl, Hubert Lamb charted its movement over the 14-day period.

He suggested that cyclonic activity was concentrated over Britain for the first six days and then moved north. On the seventh day, another system arrived from the west and marched across the country into northern Europe.

The 1680s and 1690s were arguably the coldest two decades since the ice retreated about 12,000 years ago

Looking at records of barometric pressure from the time, he noted a "deep low pressure system", with London experiencing the "sharpest" pressure changes. His analysis of the source material found the lowest pressure of 950 millibars (mb) over central England.

"Depressions generally form in the mid-Atlantic and are driven across the Atlantic by the famous jet streams, which steer cyclones," says Wheeler. "Sometimes a cyclone is benign, but they are areas of low pressure and they bring cloud and rain."

But do we know why this area of low pressure was so forceful?

One reason could have been that a sharp contrast in temperature caused a particularly deep cyclone, suggests Wheeler.

"When they're as deep as that, they normally result in a big temperature contrast between the polar latitudes and the tropical latitudes," says Wheeler. "So there's a suggestion that, although we don't have air temperature records for the Atlantic, you could have expected a steep temperature gradient north to south. That's the thermal energy inequality that gives rise to these cyclones."

At the time, the country was in the so-called Little Ice Age.

"It's quite possible that the chilliness may well have contributed to the storm, but like all these things they are multi-causal," says Wheeler. "Certainly as far as the British Isles were concerned, the 1680s and 1690s were arguably the coldest two decades since the ice retreated about 12,000 years ago."

One theory about the storm's origin was that a hurricane in New England had drifted across the Atlantic.

"We are told they felt upon that [Florida and Virginia] an unusual Tempest a few days before the fatal 7th December," wrote Defoe. But he gave no source.

It is not clear whether Beaufort was directly inspired by Defoe's work

While it was the hurricane season and hurricanes can drift, Wheeler found no clear evidence to support this theory. Lamb, however, writes that there is "some support" for the idea.

Certainly, the winds were hurricane-force. Based on early instruments and charts, Lamb estimated that the strongest winds in the system were about 150 knots. Surface wind speeds seem to have been up to 80 or 90 knots (approximately 140-155km/h or 87-96mph), with "gusts and squalls probably much stronger".

How much did the Great Storm influence early meteorology?

Defoe compiled a list of terms – a "Table of Degrees" – to describe wind forces in his 1704 book. A link is often made between Defoe's table and the Beaufort scale, which was devised a century later and is now used throughout the marine world to measure wind. The two are similar in structure, but it is not clear whether Beaufort was directly inspired by Defoe's work.

As far as a lot of people were concerned, it was literally an act of God

Wheeler looked in depth at nautical vocabulary and found that an unofficial language for describing wind force existed before Beaufort's scale, but it was not Defoe's Table.

The reason why the impact on meteorology was slim was the historical context: meteorology barely existed in 1703.

Before the 18th Century Age Of Enlightenment, most Europeans believed in the divine omnipotence of a Christian God, who could communicate his wrath with the weather. Sermons from the time show that clergy interpreted the storm as a sign of God's anger at a variety of apparent misdemeanours, including the popularity of the theatre and science. Non-clerical accounts also link the storm to divine wrath. "The Winds are a Part of the Works of God by Nature," wrote Defoe.

"You can see some scientists beginning to get an acknowledgement with a rational view of the world, such as Newton," says Wheeler. "They were the tip of an intellectual iceberg, but most people had a deeply religious view of the events that they experienced. As far as a lot of people were concerned, it was literally an act of God."

Compared with other sciences, meteorology took a long time to emerge and advance. As Wheeler points out, the problem with studying weather is that an event like the Great Storm cannot be repeated in a lab.

"It wasn't until well into the 19th Century that scientists began to realise that these winds were circulatory systems, not a linear in-flow," says Wheeler. "That really didn't begin until 1820s and 1830s. Like all branches of science it was a stumbling, groping in the dark for some time."

One gave up and just wrote 'a most violent storm' and left it at that, for sheer want of anything more he could say

As well as the theological language of most accounts of the storm, there was no standardised terminology to describe weather or atmospheric processes. Forecasting and a vocabulary of meteorology would not appear until much later, in the 1860s.

An anonymous daily journal of the weather from 1703, analysed by Jan Golinski of the University of New Hampshire, gives some insight into just how differently language was used before the sciences of meteorology and climatology were established.

The diarist uses words such as "sad", "uncomfortable", "lovely", "charming", "smiling" and "cheerful" to describe the conditions and his response to them. "He described how his bodily humours responded to atmospheric circumstances. He even occasionally recounted feelings of spiritual elation or erotic union with his environment," writes Golinski.

Admirals who were obliged to record the weather struggled to find the words to describe the Great Storm.

"It was so severe, none of these poor captains had ever experienced it before, so they didn't have any yardsticks to base the description on," says Wheeler, who studied Royal Navy logbooks at length. "One gave up and just wrote 'a most violent storm' and left it at that, for sheer want of anything more he could say."


However, there are clear signs of scientific interest in the event. The Royal Society, which had been founded a few decades earlier in 1660, released a special edition of its journal Philosophical Transactions, which included accounts detailing temperature, barometer readings and rainfall in the preceding months.

A few years after the Great Storm, an English Admiral fleet was wrecked on the rocks of the Scilly Isles in severe weather and many sailors lost their lives. In response to the tragedy, the Board of Longitude was established to determine longitude at sea, so that ship navigators would have a better idea of their exact position.

While the Great Storm did not have a similar official impact, the written records show that it piqued an early scientific curiosity about extreme weather events. This in turn led to the meteorology we use today.


