Autumn 2000 western Europe floods

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Autumn 2000 western Europe floods
Shrewsbury Abbey from the west - geograph.org.uk - 56158.jpg
Shrewsbury Abbey on November 1
Duration mid-September 2000— mid-December 2000[1]
Fatalities 20
Damages Estimated to exceed $2 billion[2]
Areas affected
United Kingdom, Italy, France, Switzerland, Spain, Netherlands, Ireland, Denmark, Norway, Slovenia

The Autumn of 2000 was the wettest recorded in the United Kingdom since records began in 1766.[3][4][5]

Several regions of Atlantic Europe from France to Norway received double their average rainfall and there were severe floods and landslides in the southern Alps.[6] In October and November 2000 a successive series of Extratropical cyclones caused severe flooding across the UK.[7][8]

The United Kingdom saw the most extensive nationwide[9] flooding event since the snow-melt of 1947.[4] Prior to 1947, three similar events occurred in the second half of the 19th century where prolonged rainfall led to widespread flooding throughout England in the month of November, namely 1894, 1875, and 1852.[3]

The combined affect of the storms across Western Europe caused flooding throughout the United Kingdom. Two storm events (Nicole and Oratia) 28 November to the 3 November, and the storm Rebekka from 4 November, resulted in continuous flooding.[10][11] 10,000 homes were flooded in 700 locations.[4] Peak flows on the Rivers Thames, Trent, Severn, Wharfe and Dee were the highest for 60 years. The River Ouse in Yorkshire reached the highest level since the 1600s.[4]

In the United Kingdom a series of severe floods affected large parts of the country in the Autumn of 2000. The worst affected areas were Kent and Sussex during October and Shropshire, Worcestershire and Yorkshire in November. The Autumn of 2000 was the wettest on record in the England and Wales precipitation record with several major rainfall events causing flooding in different parts of the country during October and November. England and Wales had an average of 503 mm of rain from September–November exceeding the previous record by nearly 50 mm.[12]

Meteorological background[edit]

A succession of slow-moving low pressure systems crossed the UK during Autumn 2000 associated with the jet stream being in a more southerly position than average.[13] The flooding in Kent and Sussex resulted from a succession of thunderstorms passing along a near-stationary front.[14] Much of the rock in this area is impermeable and there had already been significant rainfall in the south-east allowing for increased surface flow and river levels. Several fronts passed over central and northern England in the following weeks causing flooding in Shropshire, Worcestershire and Yorkshire.

Prelude[edit]

The rainfall for this period in the three preceding years had been above the 1961-1990 average.[14] The previous spring was unsettled, with April and May particularly wet,[8] which increased the aquifer recharge season.[14] Heavy rain was also seen in June, leading to high river levels and some flooding in Yorkshire.[8]

September 2000 was generally unsettled, with wet periods between 14-19. This resulted in some flooding on 15 September around Portsmouth and Southsea as a pumping station at Eastney failed after 58 mm (2.3 in) of rain fell in 4.5 hours, being the heaviest rain since 1986 in the area. Total rainfall was also measured at 65mm in Havant making this a 1 in 108 year storm event.[15] Storms affected Flanders in Belgium 15 September, with tornados reported in the municipalities of Zwalm, Antwerp and Erpe-Mere. Flooding affected the regions of Ghent and Kortrijk.[16] 24 out of 27 UK Met Office regions except northern Scotland received higher than normal rainfall during the month, making this the wettest September since 1981.[5]

Ex-Hurricane Isaac, October 2–4[edit]

Ex-Hurricane Isaac crossed the Atlantic with eye still visible on October 2,[17] before it lashed the west of the British isles with near gale force winds on October 3, before merging with another extra-tropical low on 4 October north of Scotland.[18] Early October 2000 brought more than the monthly average rainfall in the first 10 days to the southeast of England.[19]

Ex-Tropical Storm Leslie, October 9–14[edit]

Ex-TS Leslie (Imke/Heidrun[20])
Formed 7 October 2000
Dissipated 14 October 2000
Lowest pressure 963 mb (28.4 inHg)[21]
Highest gust 0 km/h (0 mph) in
Areas affected Western Europe

A complex of low pressures, named Heidrun & Imke[22] by FU Berlin formed from the remnants of Tropical Storm Leslie (ex-Tropical Storm Leslie formed 30˚N 76˚W on 5 October, swept westwards and merged with a front on 7 October and reintensified to become a storm south of Great Britain with winds of 40-50 knots reported in the Bay of Biscay).[23]

Area of convective storms stalled over the Sussex and Kent.

  • 9 October: two complex low pressure systems brought more fronts and 25-40mm of rain over Sussex
  • 10 October: a Low developed over Scotland, with gales and heavy showers over Sussex bringing 10-15mm of rain
  • 11 October: the Low over Scotland became stuck, with a new Low arriving over Central England, producing gales over the whole UK and 15-30mm of rain over Sussex.
  • 12 October: the Low drew moist air from the Bay of Biscay over Southern England where a line of heavy, localised thundery showers formed. They tracked northwest over Sussex, bringing 150mm of rain overnight to Uckfield. Only 5-10mm fell in some other areas.[24]

Affected areas[edit]

Kent[edit]

Homes in Yalding and Maidstone were flooded, however there had been fears that a high tide might lead to the River Medway bursting its banks. This threat passed preventing much more widespread damage.[25] Evacuations took place in some villages in the county.

Sussex[edit]

On 12 October many roads were flooded across both West and East Sussex including the A21 and A22. A lifeboat crew rescued 20 people trapped in a supermarket in Uckfield and others were rescued by helicopter.[26]

Shropshire[edit]

Shrewsbury, Ironbridge and Bridgnorth flooded as the Severn breached its banks and reached its highest levels in 53 years.[27]

Worcestershire[edit]

The Severn breached its banks in many parts of the county, including at Bewdley, Worcester and Upton-upon-Severn. In Worcester, the Severn peaked on 3 November at its highest level in 53 years. The river remained in flood for several days however and the main road bridge in the city was closed. Homes were flooded in Diglis as well as many businesses on the city's waterfront and the cricket ground. In Bewdley, the floods led to renewed calls for flood defences in the town.[28] These were completed in 2006 and have since reduced the impact of flooding on the town.

Yorkshire[edit]

The Ouse in flood, York

Flooding affected York during the summer and autumn of 2000 as the River Ouse reached its highest levels since records began. The floods cost the city council in excess of £1 million and 40 people had to be moved from their homes.[29] The floods were the worst in 375 years; more than 300 homes were flooded and the army were called in to help with flood relief efforts.[30]

Aftermath[edit]

Attributing flood risk to climate change[edit]

In 2011 a team of climate scientists from the University of Oxford, the Met Office, ETH Zurich, the National Institute of Environmental Studies in Japan and Risk Management Solutions Ltd. published an article on the role of man-made greenhouse gas emissions in the Autumn 2000 floods in the UK.[31] The risk of major flooding occurring during October and November 2000 was estimated to have increased due to anthropogenic greenhouse gas emissions. The team used thousands of model simulations run on the personal computers of members of the public through the Climateprediction.net project.

Warm sea surface temperatures in the English Channel and Norway,[32] along with an abnormally warm North Atlantic, added moisture and energy to weather systems as they crossed the UK.[8] September was the wettest since 1981, October the wettest since 1903 and November the wettest since 1970. Overall the autumn of 2000 was the wettest since 1872, and more rain fell in September, October and November than in any other 3 month period since rainfall records began in 1727. Climatologically it was calculated that Autumn 2000 was a 1 in a 500 year event, assuming a static climate."[8]

Government report[edit]

Defra commissioned an independent review by the Institution of Civil Engineers under George Fleming.[33] The review was to consider methods of estimating and reducing flood risk and look at whether flood risk management could make more use of natural processes. Other terms of reference included the possible impact of climate change and experience of other countries. The resulting report entitled Learning to Live with Rivers specifically criticised a reluctance to use computer models and inadequate representation of the dynamic effects of land use, catchment processes and climatic variability. More broadly, the report noted that sustainable flood risk management could only be achieved by working with the natural response of the river basin and by providing the necessary storage, flow reduction and discharge capacity. It concluded that floods can only be managed, not prevented, and the community must learn to live with rivers.

The report found that damage was reduced by flood defences and by timely warnings and evacuations where the defences could not hold back the water. As a result 280,000 properties were protected from the floods, but over 10,000 properties were still flooded at an estimated cost of £1 billion.

References[edit]

  1. ^ "The UK record-breaking wet Autumn 2000". UK Universities Global Atmospheric Modelling Programme Newsletter. Retrieved 27 February 2012. 
  2. ^ "Rising Temperatures Bringing Bigger Floods". Science Magazine. Retrieved 15 March 2012. 
  3. ^ a b "Preliminary Report of U.K. Flood Damage From Increased Rainfall in November 2000.". Risk Management Solutions. Retrieved 24 February 2012. 
  4. ^ a b c d "The wet autumn of 2000". UK Met Office. Retrieved 24 February 2012. 
  5. ^ a b "The Autumn 2000 Rains and Floods". UK Parliament briefing paper. Retrieved 24 February 2012. 
  6. ^ Blackburn, M.; B. J. Hoskins (2001). "Atmospheric variability and extreme Autumn rainfall in the UK". met reading. Retrieved 24 February 2012. 
  7. ^ "unknown". NERC. Retrieved 27 February 2012. 
  8. ^ a b c d e Paul Hudson. "The 10th anniversary of the Autumn 2000 floods". BBC. Retrieved 15 March 2012. 
  9. ^ "The 2000/01 Floods — a Hydrological Appraisal: Introduction and Overview". NERC. Retrieved 24 February 2012. 
  10. ^ "What is a flood? Defining flood loss occurrences for reinsurance purposes". Munich Re Group. Retrieved 22 February 2012. 
  11. ^ "Lessons Learned: Autumn 2000 floods" (PDF). Archived from the original on 2007-09-27. Retrieved 2009-05-18. 
  12. ^ Marsh T and Dale M (2002). "The UK floods of 2000-2001: A hydrometeorological appraisal.". Journal of the Chartered Institute of Water and Environment Management 16 (3): 180–88. doi:10.1111/j.1747-6593.2002.tb00392.x. 
  13. ^ Blackburn M and Hoskins B (2001). Atmospheric variability and extreme Autumn rainfall in the UK. 
  14. ^ a b c "The UK Autumn 2000 floods". WWF/climateprediction.net. Retrieved 24 February 2012. 
  15. ^ "Preliminary Flood Risk Assessment". Portsmouth City Council. Retrieved 27 February 2012. 
  16. ^ "Inondations" (in French). Royal Meteorological Institute Belgium. Retrieved 9 April 2012. 
  17. ^ Donguy, Patrick; Daniel Pochic (May 2001). "Les photos du mois:De la ligne de grains à la tempête - Octobre 2000". La Météorologie (in French) 33. Retrieved 23 March 2012. 
  18. ^ "Hurricane Isaac Tropical Cyclone Report". National Hurricane Center. NOAA. Retrieved 25 February 2012. 
  19. ^ "U.K. Floods, October 13-14, 2000". Risk Management Solutions. Retrieved 24 February 2012. 
  20. ^ "Rétrospective Des Catastrophes Naturelles Survenues en 2001" (in French). Munich Re Group. Retrieved 4 March 2012. 
  21. ^ "British Isles weather diary". reading.ac.uk. Retrieved 10 March 2012. 
  22. ^ "Schauer werden von stürmischen Böen begleitet" (in German). rp-online. Retrieved 4 March 2012. 
  23. ^ Mariners Weather Log 45 (1). April 2001 http://www.vos.noaa.gov/MWL/apr2001.pdf |url= missing title (help). Retrieved 9 March 2012. 
  24. ^ "Uckfield Case Study: What caused the heavy rain of 12 October 2000?". Geographical Association. Retrieved 25 February 2012. 
  25. ^ "Relief as flood threat eases". BBC. 14 October 2000. Retrieved 2012-04-06. 
  26. ^ "Floods cause chaos". BBC. 12 October 2000. Retrieved 2012-04-06. 
  27. ^ "Time shift: 2000 Floods". BBC Shropshire. Retrieved 2012-04-02. 
  28. ^ "Floods Round-up". Worcester News. Retrieved 2012-04-02. 
  29. ^ "York counts cost of 2000 flood". BBC. 13 August 2004. Retrieved 2012-04-02. 
  30. ^ Dennis, I. A.; MacKlin, M. G.; Coulthard, T. J.; Brewer, P. A. (2003). "The impact of the October-November 2000 floods on contaminant metal dispersal in the River Swale catchment, North Yorkshire, UK". Hydrological Processes 17 (8): 1641. doi:10.1002/hyp.1206.  edit
  31. ^ Pall P, Aina T, Stone DA, Stott PA, Nozawa T, Hilberts AGJ, Lohmann D and Allen MR (2011). "Anthropogenic greenhouse gas contribution to flood risk in England and Wales in autumn 2000". Nature 470 (7334): 382–385. doi:10.1038/nature09762. Retrieved April 2, 2012. 
  32. ^ Benestad, R. E.; Melsom, A. (2002). "Is there a link between the unusually wet autumns in southeastern Norway and sea-surface temperature anomalies?". Climate Research 23: 67. doi:10.3354/cr023067.  edit
  33. ^ Fleming, George; et al. (November 2001). "Learning to live with rivers" (PDF). Institution of Civil Engineers. Retrieved 2012-05-18. 

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