A Flood Alert was issued for Upper River Colne and Radlett Brook in Hertfordshire on 24th October 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 0.34m, peaking at 0.45m, while the River Colne at Farlows Bridge climbed 0.21m.
Environment Agency advice issued
Rising river levels this evening may lead to flooding. Flooding is possible from the evening of Saturday 24 October due to heavy rainfall from Storm Austen and Boelo. Locations most affected will be low lying land and roads near rivers. Further heavy rain is forecast for this evening. We expect river levels to peak tonight and begin to fall during tomorrow morning, Sunday 25 October. We are monitoring rainfall and river levels . Take care and avoid walking, cycling or driving through flood water. This message will be updated by 10:00AM on Sunday 25 October or as the situation changes.
Monitoring gauges during this event
| Station | River | Rise | Peak |
|---|---|---|---|
| Thorney Mill Road, West Drayton (Temporary) | River Colne | +0.34m | 0.45m |
| Farlows Bridge | River Colne | +0.21m | 0.66m |
| Iver, Clisbys Bridge | River Colne | +0.16m | 0.53m |
| Willowbank | River Colne | +0.12m | 0.95m |
| Denham Colne | River Colne | +0.11m | 0.25m |
| Colney Street | River Ver | +0.09m | 0.26m |