Public tool · South Yorkshire
SY Flood Watch
Environment Agency flood warnings, recent rainfall and long-term flood susceptibility for Sheffield, Rotherham, Barnsley and Doncaster — on one map, kept as three separate answers.
Free, no account, works in any browser. It reads public Environment Agency data and is not an official warning service.
What it shows
Three questions, answered separately.
Give someone the page for five seconds and they should be able to answer all three independently — not come away with a single colour.
Warnings now
Official Environment Agency flood warnings and alerts, drawn as their real flood-area polygons. Every card carries two ages: when the feed was last checked, and when the EA last changed the message.
Conditions developing
Rainfall observed at EA telemetry gauges, with a validated one-hour total where four consecutive readings exist. Timed by the newest reading, not by when we last called the API.
Areas susceptible
The long-term modelled likelihood of flooding from rivers and the sea, taking flood defences into account. Background probability — not a forecast, and not a statement about today.
How it is built
Rules it will not break.
Three answers, never one
An official warning, this afternoon’s rain and a hundred-year probability are different kinds of fact. Collapsing them into a single "flood risk" reading is the mistake this tool exists to avoid.
Absence is never reassurance
If a feed fails, the tool says so. It never renders missing data as an all-quiet state, and the words for that are banned from the codebase by a test that fails the build.
Everything carries its age
No number appears without saying how old it is and where it came from. A response fetched seconds ago can still carry an hour-old reading, and the interface says which it means.
This is not an emergency service.
SY Flood Watch presents Environment Agency data and nothing more. It does not issue warnings, it cannot see every kind of flooding — surface water in particular — and no warning showing on it does not mean no flooding.
For the official picture, use the Environment Agency flood service. If there is a danger to life, call 999.
Built on open data.
Flood warnings and rainfall from the Environment Agency real-time API; flood susceptibility from its Risk of Flooding from Rivers and Sea assessment; county boundary from ONS. Used under the Open Government Licence v3.0, with full attribution inside the app.