Wildfires have been in news this year, perhaps most notably in Hawaii, where hurricane winds, parched grass, and electrical sparks combined to create a fire that consumed a town. Closer to home, fire services were stretched to the limit when wildfires struck across the UK last year. This Hazards Forum event demonstrates how this type of fire is evolving in response to climate change, and how our response must evolve too.

From diverse fields, the three expert speakers, Megan Pearce, Guillermo Rein and Rob Stacey, share their knowledge of wildfire, revealing how it is a complex scenario with many interlinking factors, including human behaviour and environmental factors. They consider how it can be considered a ‘semi-natural hazard’, where though conditions necessary for a fire to start are largely determined by environment, four times out of five, it is humans who cause the ignition. And the impact of
climate change is an inevitable part of every presentation.
Importantly, each speaker presents clear recommendations for what can and should be done to learn lessons, adapt systems and share knowledge to better fight, control and manage wildfires. As Rob Stacey makes clear, it is certainly not a job for the fire service alone. These summaries give a flavour of each presentation. Watch the full event or read the transcript for the full experience.

Megan Pearce, consultant in the Sustainability and Environmental Assurance team at Frazer-Nash. 

‘Wildfires: The cascading risks for industry’

Wildfire is a complex, unpredictable and evolving hazard that needs to be countered by a ‘vast’ web of resilience, Megan Pearce explains. She defines wildfires as ‘any uncontrolled vegetation fire that requires a decision, action, or suppression’, reliant on the three key factors of fuel, weather, and ignition. ‘Fuel’ includes vegetation, and includes the type and amount of it, and most importantly, its moisture content. Temperature, humidity, and precipitation all have a part to play in the moisture content of live or dead vegetation, and wind direction and speed are also important in creating ‘fire weather’ conditions. For example, a fast-moving warm, dry easterly wind, bringing air from across the continent, is perfect for creating fire weather conditions in the UK.

Then thirdly, ignition. This can be natural, for example, from lightning strikes. But in four out of five cases, it is human-caused ignition – a discarded cigarette, a neglected campfire or arson. She says: ‘Once light, these factors all combine and affect the intensity and rate of spread of the wildfire’ She stresses how we need to look beyond the burned assets and consider how a wildfire destroys surrounding critical infrastructure such as power, water, communications and transport. She says: ‘These are important due to their interdependencies, and any failure of one particular link can cause cascading failures down the chain.’ Direct loss of life from the fire itself, or indirect loss of life due to ongoing air quality issues, were perhaps the most unfortunate consequences to consider.

The wildfires that broke out on the island of Maui, Hawaii, on August 8, 2023, show what happens when wildfires reach a residential or urban areas. The historic town of Lahaina was reduced to ashes, leading to the deaths of around 100 people who were unable to escape the rapidly moving blaze that engulfed their homes and streets. More than 30 people are still considered missing. Megan set out the factors that led to the devastation: ‘Since 2008, 90% of Hawaii is seeing less rain than it would have done 100 years ago. Combined with, at the time, current high winds with Hurricane Dora, the warm temperatures and the very low humidity meant that there was a red flag for increased fire risk danger. ‘The loss to industry from the business closures and the loss of tourism is estimated to be working out about $11 million a day since it happened, and this is still ongoing. ‘Unfortunately, also over 100 people lost their life.’ She adds that Hawaiian Electric Company are facing criticism – and a class action lawsuit for loss of life – for not shutting down the power during the high-wind warnings, allowing sparks to be created.

Looking ahead, she sees the change in future fire weather conditions as the greatest influence on wildfire. She says: ‘Climate change will result in an increased frequency of wildfire globally and in the UK, and it will require collaboration across public and private sector to drive effective prevention, mitigation, response, and preparedness.’ The impact of climate change is there to see in the weather records: from 1979 to 2019, fire weather days increased globally by nearly 29% and, over the same period, the length of fire seasons significantly increased across 25% of Earth’s vegetated surfaces Megan considers our resilience to wildfire and identifies many questions that still need answers.

Though the latest UK climate risk assessment identifys several beneficial actions that could be taken over the next five years to mitigate and respond to wildfire risk, there is little quantified evidence about the risk to infrastructure assets and a need for applying consistent standards of resilience. ‘The web of resilience is vast, and mapping the connections and dependencies is absolutely crucial for risk management and assessment.’ She shares a graphic, which presents three lines of defence framework for building resilience to wildfire (here applied to applying this to the electricity grid). ‘I think it really captures the three elements of resilience very well, from the first line of defence – of prevention – second line of defence of mitigation and response, and the third line of defence, recovery preparedness. All three of these elements would need to be considered across industry and supply chains to be prepared for this emerging wildfire risk.

Guillermo Rein is Professor of Fire Science, Department of Mechanical Engineering, Imperial College London, and Editor-in-Chief of the journal Fire Technology.

‘Protecting Communities and the Environment from Wildfires: Past, Present and the way forward’

Fun primary school lessons about the Great Fire of London are an asset, according to Guillermo Rein, because they teach children about the components of fire. ‘The kids in London understand the problem of a fire that is not just in a building, but it’s multiple buildings,’ he says. ‘They understand the role of winds.’ Guillermo says the lack of wind very likely saved London from another ‘great fire’ on 19 July 2022, when a spate of wildfires gave the London Fire Brigade (LFB) its busiest day since the Second World War. He says: ‘Imagine, even with the LFB here, imagine if 19th of July last year was even a bit windy. That would have been really scary.’

Wildfires hit Dagenham, Epping Forest, Harrow, Hounslow, Croydon, Twickenham, Upminster, and most notably, Wennington, where 41 houses were destroyed, many within minutes. ‘We were so lucky,’ he says. The importance of wind is understated, he says. ‘It is a multiplier of the hazard. If you have a bad situation with a dry fuel but you don’t have wind, you can handle it. There are ways of mitigating it. But if you have wind, you cannot stop it. That’s why the Met Office is so important in determining the daily fire risk. ‘As a fire scientist, a mechanical engineer, I was thinking, why did you go to atmospheric scientists if the fire happens here on the ground?’

The Met Office understands a lot of the variables that matter: the wind and the moisture of the fuel. Guillermo describes research that demonstrates the effect of wind on fire spread. With no wind, flames remain vertical and move slowly, whereas in windy conditions, they are propelled into the next fuel source – be that grass, trees or buildings – moving very fast and exponentially.

Wind was a factor in a different way in Lahaina. Hurricane-force winds caused overhead electricit wires to swing and touch, creating countless sparks that caused the grass to ignite. ‘A grass fire is very easy to extinguish, but the fire brigade was unable to stop it because of the wind, and then it entered the wild-urban interface … it was spreading faster than people could evacuate and burnt everything. We’re talking about 10,000 evacuees… Ahundred people die. We’re talking about 2,500 houses lost completely, and the community literally has now to go into emergency resilience and it will take many years to recover.’

A month after London’s wildfires, Guillermo’s student Jamie John chose them as the subject of his master’s thesis. He got open access to the LFB’s data, and then had to create new fuel fields because there was no field for wildfires, which were not considered urban events. Jamie’s research, visualised as coloured wheel graphs, revealed ‘fire waves’ (as opposed to ‘heat waves’) striking the LFB on specific days – including 19 July 2022, but also on days in 2020, 2018 and 2010. ‘What you can see are these are the days that the LFB was extremely busy fighting fires, not just attending, checking and doing a little bit of work, but these were intense fires.’ (Validating the approach, Bonfire Night on November 5 is evident as a slim orange line, cutting through the graph every year.)

In what Guillermo believes to be a first for a city, Jamie went on to cross-correlate the LFB data with Met Office data, and looked at the relative humidity of London, which is drier in the summer and wetter in the winter. He realised he could start to explain the number of wildfires seen in London using meteorological variables. This ultimately led Jamie to recognise the significance of the vapor pressure deficit (VPD). ‘The higher this variable is, the drier it is. This variable is more powerful or more meaningful than the
temperature or the humidity,’ Guillermo explains. Jamie found that if the VPD is above 700 Pa for 10 days, it correlates with an incoming fire wave. This could offer a way to see fire waves coming’, says Guillermo. ‘If the LFB, through the Met Office, takes a look at the VPD and sees one day above 700 Pa, three days above 700, four days, seven days, now “deploy, a fire wave is coming”. This should be importance to cities like London that are proud of their green open spaces. ‘We want to protect our communities,’ says Guillermo. ‘We want to study wildfires with a premise that we need to understand what we are dealing with.’ Understanding wildfires will help firefighters manage them, rather than just fight them, he says.

Rob Stacey is Wildfire Team Leader and Project Officer for Northumberland Fire and Rescue Service

‘UK Fire Rescue Service response to the increasing risk of wildfires’

Burdonside, Forelaws Forest, Canford Heath, Barnsley, Lincolnshire, Pontefract, Gloucestershire, Studland Heath, Redesdale Forest, 16 sites around London. Rob Stacey makes it clear that wildfires are having an impact across the UK, from Northumberland to Dorset. And data shows they are likely to be more frequent, severe and disruptive.
‘As a society, we need to learn to adapt and live with wildfires,’ he says. ‘If conditions are right, it’s hard to stop wildfires happening.’

His slides tell the wildfire story of July 2022:

• Burdonside, Northumberland – 139 hectares (139 rugby pitches) burnt when a controlled fire got out of control
•  Fourlaws Forest, Northumberland burned for a week, next to wind turbines
•  Camford Heath, Dorset – 17 hectares of special scientific interest destroyed in a fire with 80 firefighters and 25 vehicles in attendance

‘In the space of July, we had 16 fire and rescue services go into major incident status … all of those services are starting to be next to each other, so their ability to help the neighbour then becomes stretched. This becomes an issue of national resilience. It shows that wildfires have that potential to do that.’ Rob balances this stark reality by sharing the concerted effort being to do more than ‘respond’ to fires that ‘are way beyond our control’.

– 45 highly trained National Wildfire Tactical Advisors (including Rob) who offer specialist advice, across borders
– online training modules, giving standardised foundation level training across all fire and rescue services
– investing in new equipment, such as off-road vehicles and drones
– research into protecting firefighters from the toxins and contaminants of wildfires, in collaboration with University of Central Lancashire
– developing wildfire response plans.

Rob explains this is collecting information about high-risk areas and developing plans for how to fight wildfires there before they happen – as is done for factories, for example. He says: ‘We’ve got that information available to all crews that are responding – we can make decisions quickly and safely. If we turn up to an area we don’t have any information for, it can take hours, if not days, to find out who owns it, where the water sources are and so on. If we can get al that work done beforehand, we can have a better response.

Rob’s service in Northumberland has been doing this for decades and is sharing their template with other fire and rescue services, and it is being used in Cumbria, Tyne and Weir, Durham and Darlington, as well as internationally – quarterly meetings with colleagues in the Netherlands, informal northwest Europe wildfire group, and the UK Wildfire Conference 2024.

Rob says, ‘The great thing is that these events keep getting bigger and bigger. It’shelping us in the UK to keep going forward with things ‘A couple of years ago, none of this existed. This was very much a locally driven approach to
wildfires. But now we’re mobilised. We are working at all of those scales: local, regional, national. Then the final thing is lessons learned.’

The final thing is lessons learned, and for the first time this year, the Fire and Rescue Service will hold a structured debrief for 2022, gathering more information and details about injuries to firefighters in the public, evacuations, property losses, extreme fire behaviour. It will include
responses from all the UK’s fire and rescue services, which Rob says, ‘is unprecedented’.

A report is going to be published soon, which will create an action plan for National Fire Chiefs Council, the Wildfire Tactical Advisors, and for the fire and rescue services. ‘That’s going to shape what we do for the next 12 to 18 months, but importantly, we need to keep repeating that year-on-year.’ He says fire and rescue services are great at doing this locally, having a get-together to debrief after every incident. ‘We talk about what went wrong, what went well, what didn’t go well, what do we need to know next time. We need to work with academics … industry… people in other sectors, land management sectors. We need to work with government. It is a shared problem, and we need shared solutions to it because we’ve got lots of stakeholders involved.

He says there is a need to collaborate and involve more people in these discussions, continuing to reach out. Perhaps especially to the children Guillermo talked about in his presentation. ‘We need to have that consciousness of Guillermo’s children about the Great Fire of London –wildfires need to be part of that as well. There is a case that we need to be building this into children’s education so that they are aware of these risks and hazards going forward, and that wildfire is not something that is distant and happening in other countries. This is happening in the UK, and it’s going to become more prevalent.

Panel Discussion

A lively discussion followed the presentations. Questions included:

1) Are wildfires putting more CO2 into the atmosphere than human activity?

Guillermo – ‘Not all wildfires are net contributors to carbon emissions. If the forest is allowed to grow back again, so if we don’t build houses, but we let the forest come back, we have seven years to make that event carbon neutral. If the forest doesn’t come back again in seven years, then the event … becomes a net carbon emission.’

Rob – ‘Wildfire is part of the natural system. If we exclude it and we prevent all ignitions, we don’t do any prescribed burning, we don’t manage the land and we let vegetation do its thing, then we create situations where we will have massive releases of CO2 … it has to be integrated more into what we do on a regular basis.’ ‘Anecdotally, we had a wildfire in Otterburn Ranges in 2018, and a very rough estimate was 7 km 2 burned over a month. Based on the surface, the carbon lost from that fire was greater than the MOD’s carbon budget for the year … and that’s just surface, it was a deep peat fire. We don’t know how deep that went. Massive emissions basically from that fire’.

2) Clearly wildfires threaten towns and potentially whole cities. So, should there be some changes in urban planning guidance and building regulations?

Guillermo – ‘Definitely. The fire safety community is always playing catch up… we say, “Oh, we want to protect the whole of London against the possible worst fire”, immediately they will say there is no money. But then something happens and then they ask us, “Oh, by the way, tomorrow you need to develop” …’ We know at some point we will be asked to change the regulations to protect the built environment from wildfires. That’s one of the reasons why I presented the work today, because this makes the point that we need to start protecting our buildings from a hazard that comes from the outside, not just a hazard that comes from the inside.’

Rob – ‘We need to look at landscape engineering… if we can incorporate wildfire risk and management into a landscape scale, that will help protect structures as well. ‘My colleagues and I are working with Defra and the tree planting scheme – putting millions of trees in – that will fundamentally change our wildfire risk, particularly for the first 12 years of those young trees. They are potentially quite a big hazard for us, so, we have to make sure the design of where they go in protects the asset – we don’t want trees to be planted and then just burn – but then also protects things around them as well. It’s all part of a complex picture, but it’s important.’ He also says the Fire and Rescue Services are working to replicate the ‘fire wise’ communities in the US, which encourage people take action to protect themselves.

Megan – ‘Some of the most at-risk significant assets are probably going to be a little bit more rural. If you think about industry, which you typically locate away from city centres, for example – take nuclear as an example – to protect people. They’re more likely to be in an environment that is at risk but also if they come into contact with the wildfire, that has significant hazard and repercussions.’

3) How can we deal with the conflicting pressures of different natural hazards? I work in the flood management sector, and we use tree planting as a source of natural flood management.

Megan – ‘My first response would just be communication … sectors, whether that be an industry or public sector in general, don’t talk to each other very well… all these things are interconnected. As we talk about these compound hazards, flood is one, wildfire is a very complex one, and there has to be communication between the responses and the actions that are taken to mitigate and adapt to them so that you don’t cause issues within the other… We know from evidence from other countries, such as the South of France, wildfires ripped through an area, removed the vegetation, and they’re very rapidly followed by flash floods because the vegetation has been removed by the wildfire. You have to have the wildfire specialist talking with the flooding specialists. Part of what they do after wildfire now is go in and block gullies to try and reduce the flood risk that will come as a result of that’.