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Flash flooding from rivers

The information on this page has been provided by the Environment Agency and was correct at the time of upload.

Flash flooding usually results from intense and heavy rainfall. It occurs in areas where rivers are very responsive to heavy rainfall. Unlike most other types of flooding, the localised nature and speed of the river response means that flooding can occur before flood warnings are issued.

Precisely where flash floods will strike can be difficult to predict accurately as it can occur in places with no recent history of flooding. It is therefore vital that, even if flooding hasn’t happened in your community for a long time, you know what to do and how to stay safe.

Flash floods can also occur on sunny days when a storm has struck higher ground upstream. This means that it is important to be aware of the signs of flash flooding even on dry days.

Examples of the devastating effects of flash flooding were seen in Boscastle (Cornwall) in 2004; Helmsley (Yorkshire) in 2005; Coverack (Cornwall) in 2017 and Reeth (Yorkshire) in 2019.

Check your flood risk and sign up for flood warnings at or call Floodline on 0345 988 1188.


Stay safe. Know the signs.

As flash flooding can occur before flood warnings are issued it is important to be aware of the warning signs:


Be Prepared. Have a plan.

You need to take steps to prepare for flooding in advance so that you can respond quickly and calmly when it happens. This is especially important for flash floods as there is little time to respond when they do happen.


Visit to find out more about creating a flood plan.

You can download all of this information in a handy PDF leaflet here.


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The Environment Agency are working on developing this page over the next few months. Please revisit later in the year for updated information.