Mapping flood investigations.

Section 19 reports are commissioned by councils in England and Wales after flood events to investigate the causes of flooding and provide recommendations on how to prevent future flooding. This map displays information on the impacts of flooding in individual places in England contained within those reports.

The map was produced by extracting information on flood impacts from the reports using a Large Language Model (LLM). Relevant pages from each report were sent to the LLM with instructions to return information about impacts in the places mentioned and when they happened. Coordinates matching the place names were then derived using geocoding.

We recommend reading the known issues and data-quality flags below before using the map. On some laptops, side-panel scrollbars may only appear when scrollbars are enabled in the operating system settings.

The underlying data was produced by Helen Jackson of ClimateNode, and the original map interface by Kip Parker, Lead Developer at Icebreaker One, both on a pro bono basis.

The map contains information on more than 10,000 locations in England, down to street and asset level. At first, it shows high-level clusters. Select a cluster to zoom in and reveal pins for individual points of interest. Selecting a pin opens information about flood events at that location. A number on a pin indicates that several flood events are listed.

Coordinates do not show the precise location of flood impacts. They indicate the general location of the place mentioned. Most coordinates were derived from OpenStreetMap.

Many places in England share the same name—there are thousands of High Streets, for example—which makes identifying locations in text difficult. Place-name identification has been subject to rigorous human quality control and coordinates should, in the vast majority of cases, refer to the correct location.

Large Language Models can fabricate information, often called “hallucinating”. Clear extraction instructions and specific source pages reduce that risk, but cannot remove it. If a map result matters to you—for example, an event on your street or evidence for research—do not assume it is accurate. Check the cited passage in the linked Section 19 report. The map provides report links and page references for this purpose.

Section 19 reports can also contain inaccuracies. Place-name and date errors are common and were corrected where identified. The word sic indicates that the name used in a report differs from the place believed to have been intended.

Information extracted from images, tables and lists spanning pages should be treated cautiously. Images of flood-flow routes can be misinterpreted by AI; rows in large tables can be attributed to a place named on another row; and standardising complex passages can blur which impacts belong to which event. Where a paragraph describes several events, information may be repeated under each date even when not every observation applies to every event.

Most impacts in a report relate to the event being investigated, but many reports also contain flood histories extending back decades or centuries and references to other recent events. The map lists every distinct event mentioned under its own date heading.

Dates range from a precise day to descriptions such as “winter 2013–14”, “Easter 1998”, a year or a decade. Precise dates or ranges are shown where available; otherwise the report’s verbal description is used.

“Ambiguous date” means that the information concerns flooding in general, an event whose date the LLM did not identify, or flooding that happened repeatedly or at some point in a long period such as 2002–2020.

Different descriptions of the same event were harmonised where possible. For example, “Storm Babet, 18–23 October 2023” and “October 2023” may appear under the more precise range. Some duplicates may remain. Dates of investigations or remedial work were sometimes returned instead of the flood date; these were corrected where found, but some may remain.

All page references count the cover as page 1, so they can differ from page numbers printed inside a report.

A small amount of text from the preceding and following pages was normally included when material was sent to the LLM, avoiding cut-off sentences and paragraphs. Information can therefore sit on the page before or after the one cited. If you cannot find a passage on the stated page, check both adjacent pages.

References are less reliable where a list or table spans pages. To avoid breaking it apart, the whole list or table was treated as belonging to the page on which it begins.

The map covers as many English Section 19 reports as the project team could collate in September 2025. There are gaps in coverage which future updates may address.