- 22nd March 2021
- Posted by: Miranda Pont
- Category: Blog
Last week the Environment Agency highlighted that for the first time in 2021, there were no live Flood Warnings or Severe Flood Warnings in place. For anyone who lives with flood risk or who has been affected by flooding, this news of reduced flood risk will be a relief.
But how wet were the first 10 weeks of 2021? We look back at the main flood events of the last two months and explore some of the locations affected.
Storm Christoph, January 2021
Storm Christoph was the first named storm of 2021, and the third named storm of the 2020/2021 storm season. Between 18 and 21 January 2021, Storm Christoph brought strong winds, heavy rain and snow to the UK with an Amber severe weather warning issued by the Met Office. The most intense rainfall occurred over north Wales and northern England, falling on already saturated soils due to above average rainfall in December 2020, this brought localised flooding to many areas. According to the Met Office, 100mm of rain or more fell across upland areas, and for north-west England and North Wales this was one of the wettest 3-day periods on record.
The Environment Agency (EA) and Natural Resources Wales (NRW) issued flood warnings across many parts of the two countries including Severe Flood Warnings on the River Mersey, River Bollin and the English and the Welsh River Dee.
Our flood forecasting system Flood Foresight continuously monitors rainfall and river flow conditions across the UK. Using a combination of meteorological and hydrological data, and unique modelling technology the Flood Foresight system produces:
- Rainfall Screening information – a forecast rainfall amount and associated return period for up to 6 days in advance.
- Flood Forecasting – comprising combined flood extent and depth maps for fluvial flooding up to 10 days in advance.
- Flood Monitoring in real-time using data from a network of river gauges, updated every three hours, to produce real-time flood extent and depth maps.
Five days in advance of Storm Christoph, Flood Foresight indicated that flooding following the storm had the potential to impact property. An Event Response produced by our colleagues at JBA Risk Management reports on the conditions at Didsbury and Northenden on the River Mersey in Greater Manchester:
The Environment Agency filled the Didsbury basin – a flood storage basin, immediately adjacent to the river. The river level peaked at 7.1m at Didsbury and a record high of 3.27m at Northenden in the early hours of 21 January. Flood waters were reported to be ‘centimetres away’ from the top of the 1-in-150-year flood defences. Storm Christoph Event Response, JBA Risk Management
The map below shows forecast flood extent and depths, at a four day lead time for a location on the River Mersey in Didsbury, Greater Manchester.
The next map shows modelled flood extent and depths in real-time for the same location on the River Mersey.
The flooding during this period also led to transport disruption in some areas, including at this location in South Yorkshire. Forecast flood extents and depths generated four days ahead of the event by the Forecasting module showed that there may be impacts to transport networks at this location.
According to the Flood Monitoring Module, northern parts of England were most affected by the flooding following Storm Christoph, including Cheshire, Manchester, Merseyside, Lancashire and Yorkshire.
Storm Christoph was followed by Storm Darcy between 6 – 8 February, which brought more wintry storm conditions to the UK with snow and ice affecting many areas.
Want to know more?
Flood Foresight is a globally-scalable operational system providing data on rainfall severity, flood inundation footprints and depth, and flood impacts. Flood Foresight supports operational flood management in the infrastructure, insurance, utilities and civil contingencies sectors, and is designed to be compatible with existing business intelligence and decision support tools. Find out more about our flood forecasting and real time flood monitoring system at www.floodforesight.com
You can also find more information about flood resilience on our webpages.