Flash Flooding

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What is a flash flood?

Flash floods happen when an exceptional amount of rain falls in a very short time. Although flash floods are still very rare, climate change and an increase in thunderstorms means they are more likely to happen. Flash floods are extremely destructive so being prepared could save lives.

1. Flash flooding can happen suddenly. It is important to know what signs to look for in your location so you can ACT fast.

  • heavy rain or severe weather reports
  • rising water levels with churning, dark water
  • a build up of debris in rivers or streams

2. Do not walk or drive through flood water

In a flash flood most injuries and deaths happen when people try to cross flood water. It only takes 15cm (six inches) of flast-flowing water to knock an adult over, and only 60cms (two feet) of water to lift and sweep away a 4 x 4 or small lorry. There also may be hidden dangers in the water like rubble and exposed drains.

3. Plan where to go if you get caught in a flash flood

If you're in a building with at least two storeys and you believe it is safer to stay where you are, you should. Move to a higher floor and wait for instructions from the emergency services. If you're in vulnerable accommodation such as a bungalow or a basement without access to higher floors - or caught outside - you should seek shelter in the nearest two-storey building or go to a higher ground. Call 999 if you are trapped.


Flash flooding - can happen very quickly and there's often no time to issue flood warnings in advance. However, there is a free Floodline Warning Direct Service, which will give you advance warning of flooding from rivers and the sea. Sign up and check your flood risk by phoning Floodline 0345 988 1188 or visit 

Environment Agency