A Flood Alert was issued for Upper River Colne and Radlett Brook in Hertfordshire on 27th August 2026. Affected watercourses included the River Colne.
During this event, FloodRadar monitoring gauges recorded notable rises. The River Colne at Thorney Mill Road, West Drayton (Temporary) rose 0.11m, peaking at 0.13m, while the River Colne at Farlows Bridge climbed 0.09m.
Environment Agency advice issued
Rising river levels may lead to flooding this evening 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 tonight 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
Monitoring gauges during this event
| Station | River | Rise | Peak |
|---|---|---|---|
| Thorney Mill Road, West Drayton (Temporary) | River Colne | +0.11m | 0.13m |
| Farlows Bridge | River Colne | +0.09m | 0.42m |
| Iver, Clisbys Bridge | River Colne | +0.08m | 0.40m |
| Willowbank | River Colne | +0.06m | 0.91m |
In the news
- Flood alert in place for River Colne in Hertfordshire — Google News