Boscastle flood of 2004

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Looking upstream from the bridge after the flood

Looking at the Old Cornish Stores Shop

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Boscastle flood of 2004

The Boscastle flood of 2004 occurred on Monday 16 August 2004 in Boscastle, Cornwall. The village suffered extensive damage after a flash flood caused by an extraordinary amount of rain that fell over the course of 5 hours that afternoon. The floods were the worst in local memory, and a study commissioned by the Environment Agency from HR Wallingford concluded that it was the worst known flood in the village, among the most extreme ever experienced in Britain. The peak flow was about 140 m3/sec (tonnes), between The annual chance of this (or a greater) flood in any year is about 1 in 400 The probability each year of the heaviest 3 hour rainfall is about 1 in 1300 (note that rainfall probability is not the same a flood probability)

The last time Boscastle had suffered notable flooding was in 1996 as a result of Hurricane Lili, but earlier floods are recorded in 1847, 1957, 1958 and 1963. Fifty-two years earlier, to the day, the town of Lynmouth, a small town some miles further east along the north coast in Devon near Exmoor, suffered extensive damage in a catastrophic flood, in which 34 people lost their lives.

1 Causes of the flood
2 Impact
3 Trivia
4 See also
5 References

[edit] Causes of the flood

The rainfall on the afternoon of 16 August 2004, was very heavy. 200.4 mm 8 inches of rain fell over the high ground just inland from the village. At the peak of the downpour, at about 15:45 GMT, 24 mm of rain (almost one inch) was recorded as falling in just 15 minutes at Lesnewth, 2.5 miles (4 km) up the valley from Boscastle. In Boscastle itself, 89 mm (3.5 inches) of rain was recorded in 60 minutes. The rain was very localised: four of the nearest 10 rain gauges, all within a few miles of Boscastle, showed less than 3 mm of rain that day. The cause of the very heavy localised rain is thought to be an extreme example of what has become known as the Brown Willy effect.

The torrential rain led to a 2 m (7 ft) rise in river levels in one hour. A 3 m (10 ft) wave — believed to have been triggered by water pooling behind debris caught under a bridge, and then being suddenly released as the bridge collapsed — surged down the main road, Water speed was in excess of 4m/sec (10mph), more than sufficient to cause structural damage.It is estimated that 2 million tonnes (440 million gallons) of water flowed through Boscastle that day.

[edit] Impact

Around 75 cars and 6 buildings were washed into the sea, several boats were also lost, along with uprooted trees and other debris. In an operation lasting from mid-afternoon until 2:30 AM, a fleet of seven helicopters rescued about 150 people clinging to trees and the roofs of buildings and cars. Amazingly, no major injuries or loss of life were reported.

In addition to six buildings being washed away, many other buildings suffered serious flood damage or were reported unsafe. Most of the tourist attractions and shops are in the oldest parts of the town, in the areas most affected by the flood at the bottom of the river valleys. The visitor centre was half demolished, and the Museum of Witchcraft was also severely damaged. The ground floors of many buildings were covered with many inches of mud washed in by the flood waters. Following the rescues on 16 August 2004, emergency services cleared debris that had built up beneath and over the bridge at the centre of the village, and waters receded. Several buildings were demolished as a result of damage caused by the floods.

Co-incidentally, two BBC film-crews were recording separate series that involved the flood. One series, A Seaside Parish was following the life of the new local parish priest, the Revd Christine Musser, at the time of the flood, and records the events of 16 August and its aftermath in the following months. The other was Seaside Rescue, which followed various coastguard operations, including a helicopter from HM Osprey on the Isle of Portland which was involved in winching people out of flooded houses in Boscastle.

Much of the damage has now been repaired. A temporary visitors centre has opened in a Portakabin, and most of the businesses have reopened. The number of day visitors is running near to usual levels, although fewer people are staying overnight.

[edit] Trivia

Private Eye revealed that whilst 55 residents were airlifted out by the Royal Navy and Royal Air Force after the flooding, 35 BBC staff were flown in by other means.