Heatwaves and firewaves: the drivers of urban wildfires in London in the summer of 2022
File(s)
Published version
Author(s)
John, Jamie
Rein, Guillermo
Type
Journal Article
Abstract
In the summer of 2022, a series of heatwaves caused an unprecedented wave of wildfires across the UK. London, in particular, was badly affected. Its green spaces wilted, and the drying vegetation provided the fuel for wildfires. The London Fire Brigade (LFB), one of the largest firefighting organisations in the world, was overwhelmed. On 19th July 2022, it experienced its busiest day since World War II. Our work represents a first attempt to examine and quantify the link between heatwaves and wildfires in a city. We combine fire incident data from the LFB and meteorological data from the Met Office, from 2009 to 2022, identifying vapour pressure deficit (VPD) as a key driver of wildfires in the urban habitants of Greater London. Wildfire activity is characterised using the number of recorded wildfires, and the time spent at incidents by the LFB’s fire pumps. We find that VPD is able to explain up to 61% of the variation in number of London wildfires. Relative humidity, and maximum daily temperature are only able to explain 44% and 42% of the variation respectively. We find that the Met Office’s definition of a heatwave—defined for the purpose of public health—is unsuited to describe the process of vegetation drying, and propose a new definition using data from the Met Office, based on vapour pressure deficit. Further, using the time spent at incidents by the LFB’s pumps, we define and identify the concept of a firewave, in order to foresee the potential arrival of another wave of extreme wildfires in London and prepare accordingly. It is hoped that the results will be of operational value to the LFB, and lay the foundation for further work investigating the role of heatwaves and VPD in increasing wildfire hazards in cities and other urban environments worldwide.
Date Issued
2025-09-01
Date Acceptance
2025-03-31
Citation
Fire Technology, 2025, 61 (5), pp.3451-3460
ISSN
0015-2684
Publisher
Springer
Start Page
3451
End Page
3460
Journal / Book Title
Fire Technology
Volume
61
Issue
5
Copyright Statement
© The Author(s) 2025 Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/.
License URL
Subjects
Engineering
Engineering, Multidisciplinary
FIRE IGNITION
Materials Science
Materials Science, Multidisciplinary
Meteorology
Science & Technology
Statistics
Technology
United Kingdom
Urban
VAPOR-PRESSURE DEFICIT
Wildfire
Publication Status
Published
Date Publish Online
2025-05-21