The latest England flood warnings in force for the
Hertfordshire and North London region. Data supplied direct from the Environment Agency. Please refresh this page for flood risk updates. Avoid damage to property and travel disruption.
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Flood Warnings and Weather Forecasts.
Flood Warning Area: Hertfordshire and North London
Counties at risk of flooding:
Hertfordshire
Areas at risk of flooding: Upper River Colne and Radlett Brook.
Rivers At Flood Risk
River Colne
Current Flood Alert: Flood alert 3
Latest flood alert advice from the Environment Agency: Rising river levels may lead to flooding today Thursday 27 August 2026 due to forecast heavy rain and storms. Locations most affected will be Waterside, Lowbell Lane, London Colney, Warrengate Road. Flooding from surface water, where water gathers and flows off road surfaces, could also occur. We expect river levels in areas that receive the heaviest rain to respond by rising quickly. Further heavy rain and thunderstorms are forecast during the day on Thursday 27 August and into Friday 28 August. We are closely monitoring the situation and we are prepared to issue flood warnings if required. Take care and avoid walking, cycling or driving through flood water and avoid using low lying footpaths and any bridges near watercourses. This message will be updated by 05:00 PM on 27 August 2026 or as the situation changes.
Flood Level Number / Meaning
1: Severe Flood Warning Severe Flooding, Danger to Life.
2: Flood Warning Flooding is Expected, Immediate Action Required.
3: Flood Alert Flooding is Possible, Be Prepared.
4: Warning no Longer in Force The warning is no longer in force.
Hertfordshire flood warning updated at: 2026-08-27T09:39:06
For more information on flood risks and action to take for the Hertfordshire and North London region of England:
Click here:
Hertfordshire Flood Warnings
