The Lynmouth floods of 1952
The small coastal town of Lynmouth became known throughout the world for the disaster, which struck in August 1952. On the night of the 15th, after continuous rain throughout the day, the rivers of the East and West Lyn rose suddenly and filled with the waters from their Exmoor catchments. Large boulders and rocks were carried in the flow towards the village, destroying houses, roads and bridges. Many lost their lives during that dark and terrifying night. The whole of Exmoor was affected and considerable damage was caused on the Barle, Exe, Heddon and Bray but the worst effects were at Lynmouth. This is because the water draining from most of the northern side of Exmoor ends up in the East and West Lyn Rivers, which join at Lynmouth. Hundreds of thousands of years ago these rivers used to run to the sea much further to the west but during the Ice Age the side of their valley was eroded by the sea and, as a result, they fell to the sea along a much shorter and steeper course. As a result the waters descending on Lynmouth are particularly fast and erosive.


The flood was one of the most spectacular and most studied in Britain. Interest was shown in the small scale as well as the larger effects on the landscape. Green studied the effects on river courses, erosion and deposition and Gifford and Kidson studied land slipping and its causes in the upper reaches of the Exe. Whilst it is still possible to see landforms created by the flood and to calculate its flow from remaining flood channels, most of the evidence of the flood has now disappeared. At first it seemed that the flood confirmed the theory that most of the shaping of our landscape occurred during such violent events, which were perhaps hundreds of years apart. However, work by Anderson and Calver on how the great scars and piles of boulders left by the flood have largely been removed by commonplace fluvial activity has changed our view of the shaping of landscape. Few now remember the disaster but its study has had far reaching effects upon our understanding of erosion and the way we deal with floods.


Moorland Vegetation and Soils


The catchment area of the Lyn rivers totals 39.2 sq. miles, much of which is plateau drained by steep sided combes. The plateau is covered in parts by moorland grasses growing from a wet, peaty ground and in others by heather and bracken on well-drained soils.


During the 19th century the Knight family had tried to drain the northern plateau by ineffectually digging gutters to carry the water to the lowlands. Not until Frederic Knight used the steam plough to penetrate the hard pan, did thousands of acres of Exmoor become good pastureland. Yet he did not successfully drain the Chains, which, according to Burton, "remain to this day the wettest and wildest region of the moor". Despite the wetness of the Chains, the capacity of its peat to hold water has been reduced over the last century and a half by heavy grazing and burning. In addition there has been much reclamation of surrounding moor and heath in the 19th and early 20th centuries. Since 1947 there have been government grants for agricultural drainage and there is evidence that runoff is more rapid now than before that time. This rapid runoff has been blamed for the apparent increase in flash flooding.
Before examining the weather over Exmoor during 15th August 1952, it is relevant to assess the meteorological situation prior to the event. Drought had affected most of southern England during the second half of July of that year. Conditions broke down at the beginning of August to be followed by a period of changeable weather over the whole country. Maximum temperatures of 80 F were reported on only three days. Thunderstorms occurred daily in the country with the centre of activity changing from place to place. This led to an irregular distribution of the monthly rainfall. During the evening of the 6th there were severe thunderstorms over London and the Home Counties. A record daily fall of 4.83 inches was recorded at Boreham Wood, and rainfalls of "very rare" intensity were recorded