20 November 2019 - update
The JBA event response team produced an initial flood footprint and commentary (see below) on 11 November 2019 with details of the flooding at time of writing. Below is an event commentary as of 20 November.
Following our initial release, more stories of those affected in the UK floods have surfaced as flooding continues to impact many homes and businesses. Local authorities report that at least 1,758 properties are believed to have been flooded across Yorkshire, Derbyshire, Nottinghamshire and Lincolnshire, although official figures are yet to be released (The Guardian, 2019). The village of Fishlake is one of the worst affected areas.
The event itself saw a month’s worth of rainfall fall within 24 hours in parts of northern England, with a weather station in Sheffield recording its wettest autumn on record with 427.6mm of rain since 1 September 2019 (The Telegraph, 2019; Independent, 2019a).
JBA has analysed the data from the flow gauge on the River Don at Doncaster to determine the approximate annual return period of the event peak flow at the gauge. There is great uncertainty in such estimates but the water level is known to be higher than the 2007 event, which had a peak flow of 381m3/s. Using the annual maximum peak flow data from the national river flow archive, this suggests the flow exceeded the 300-year flood level. However, when including the recent peak in that data, the estimate reduces to exceeding the 125-year flow (clearly demonstrating the uncertainty in such estimates). It should be noted that these estimates are only at one location and other locations within the flooded areas may have considerably different return periods associated with the peak flows.
The Environment Agency has said that temporary defences and water pumps have helped protect over 21,000 homes and predicted that homes in Fishlake should be free of water by Sunday 24 November (Independent, 2019b).
According to comments made by PwC, insured losses could range from £80 million to £120 million (Insurance Times, 2019).
To access the latest footprint, please get in touch.
Original commentary
On 7 November 2019, persistent and intense rainfall fell across many districts in the north of England, including Sheffield, Doncaster, Bentley and Fishlake which all experienced severe flooding. In some areas, a month’s worth of rain fell in less than 24 hours (The Guardian, 2019). Around 400 homes have been flooded and 1,200 people evacuated across the areas affected (BBC, 2019).
At midnight on 7 November, a rain gauge in Sheffield recorded 85.9 mm of rainfall, with Doncaster recording 61.2 mm at the same time (Met Office, 2019). New records for river levels have been set for several gauged locations along the River Don, including Fishlake where river levels peaked at 6.87 metres on 9 November (Environment Agency, 2019). The River Don, which flows through Sheffield, Rotherham and Doncaster, is believed to have reached levels higher than that experienced in the devastating floods of 2007 which resulted in 13 deaths and damage to 48,000 properties and 7,000 businesses across the country (Yorkshire Post, 2017).
A yellow warning of rain has been introduced for 11 and 12 November, with the warning extended on the morning of Monday 11 November to cover more of West Yorkshire, Derbyshire and Staffordshire (Met Office, 2019). At the time of writing, five severe flood warnings remain in place along the River Don, impacting Kirk Bramwith, South Bramwith, Willow Bridge Caravan Site, Bentley and Fishlake (Environment Agency, 2019). However, water levels on the Don have peaked and started to recede (Environment Agency, 2019).
Our Flood Foresight system has been monitoring the recent flood events in Derbyshire and South Yorkshire and produced forecast and real-time flood depth footprints.
On 6 November, Flood Foresight indicated the potential for flooding at Meadowhall Sheffield two days in advance. The forecast intensified on 7 November and resultant flooding was seen on the surrounding access ways and railway station by 8 November.
In Bentley, Doncaster, Flood Foresight indicated property at risk on 7 November with flooding again seen on 8 November.
Flood Foresight is a system that provides flood inundation, depth and impact data before, during and after flood events. It provides a globally scalable framework for integrating the best available data for understanding flood events, including flood hazard maps, rainfall forecasts, hydrological models, river levels/flows, and earth observation. Once the event subsides, we can use Flood Foresight and observational data to develop a maximum flood footprint (extent and depths) across the event. Flood Foresight can be used for:
- Rapid loss forecasting giving you added confidence in exposure management
- Limiting exposure to live flood events by identifying underwriting embargoes based on forecast data
- Increasing client satisfaction by moving from reactive to proactive claims management
- Speeding up claims triage and adjusting and securing early access to claims support resources
- Best recovery from reinsurance hours clause by defining time of onset and duration of flooding
For more information on Flood Foresight, visit the website or get in touch. For more information on JBA's flood mapping and event response work, or to access the flood footprint, please speak to our team.
References
BBC News. 2019. Fishlake flooding: Weather warnings as more rain due. [online] Available at: https://www.bbc.co.uk/news/uk-england-50372839?intlink_from_url=&link_location=live-reporting-story [Accessed 11 Nov. 2019].
GOV.UK. 2019. Flood warnings for England - GOV.UK. [online] Available at: https://flood-warning-information.service.gov.uk/warnings [Accessed 11 Nov. 2019].
Met Office. 2019. Met Office WOW. [online] Available at: https://wow.metoffice.gov.uk/ [Accessed 11 Nov. 2019].
The Guardian. 2019. Flooding in Yorkshire – in pictures. [online] Available at: https://www.theguardian.com/uk-news/gallery/2019/nov/08/flooding-in-yorkshire-in-pictures [Accessed 11 Nov. 2019].
The Yorkshire Post. 2019. The fight to protect Sheffield from repeat of deadly floods of 2007. [online] Available at: https://www.yorkshirepost.co.uk/news/latest-news/the-fight-to-protect-sheffield-from-repeat-of-deadly-floods-of-2007-1-8611534 [Accessed 11 Nov. 2019].
Updated commentary references
BBC News. 2019. England flooding: Fishlake residents 'could be homeless for weeks'. [online] Available at: https://www.bbc.co.uk/news/uk-england-50398877 [Accessed 20 November 2019]
The Guardian. 2019. Council leaders demand huge funding rise after floods. [online] Available at: https://www.theguardian.com/environment/2019/nov/14/council-leaders-demand-huge-funding-rise-after-floods [Accessed 20 November 2019]
Independent. 2019a. UK weather: Sheffield records wettest autumn on record with more than two weeks still to go. [online] Available at: https://www.independent.co.uk/news/uk/home-news/uk-weather-forecast-today-wettest-autumn-record-flooding-sheffield-south-yorkshire-a9205421.html [Accessed 20 November 2019]
Independent. 2019b. UK weather: Flooding chaos as northern England warned of further misery. [online] Available at: https://www.independent.co.uk/news/uk/home-news/uk-weather-forecast-latest-floods-warnings-environment-agency-a9206321.html [Accessed 20 November 2019]
Insurance Times. 2019. First cost estimates to insurers given on hit from Yorkshire floods. [online] Available at: https://www.insurancetimes.co.uk/news/first-cost-estimates-to-insurers-given-on-hit-from-yorkshire-floods/1431867.article [Accessed 20 November 2019]
The Telegraph. 2019. Flood-hit areas to escape heavy rain as temperatures drop below freezing following 'biblical' downpour. [online] Available at: https://www.telegraph.co.uk/news/2019/11/09/flood-hit-areas-escape-heavy-rain-temperatures-drop-freezing/ [Accessed 20 November 2019]