Flood alert or flood warning: what is the difference?

A flood alert means flooding is possible and you should be prepared. A flood warning means flooding is expected and you should act now. A severe flood warning means severe flooding and danger to life.

Those are the Environment Agency's own definitions for England. The words are close together, but each one asks you to do something different.

| Level | Environment Agency wording | Sensible response | |---|---|---| | Flood alert | Flooding is possible, be prepared | Pack a bag, check on neighbours, keep up with updates | | Flood warning | Flooding is expected, immediate action required | Move people, pets and valuables upstairs, turn off gas, electricity and water if safe | | Severe flood warning | Severe flooding, danger to life | Follow the emergency services and leave if told to |

When the danger has passed, a warning is marked as no longer in force. That does not mean the water has gone, so take care around flood water, which can hide drains and carry sewage.

What makes flooding hard to forecast

River flooding builds up. Rain falls on the hills, runs off and reaches a town hours or days later, which gives some notice. Surface water flooding is the opposite: a heavy downpour overwhelms drains within minutes, sometimes in a place far from any river. Tidal flooding depends on the height of the tide, the wind and low pressure pushing the sea up.

Outside England

The Environment Agency covers England only. In Scotland, go to SEPA Floodline. In Wales, go to Natural Resources Wales. In Northern Ireland, nidirect has the guidance. The warnings page links to each.

One thing to do today

Sign up for free flood warnings for your address if you live near a river or the coast. Warnings by phone or text reach you when you are not looking at a screen, and at night that matters most.