Fighting fires with science?

Published Forestry Bulletin 31 March 2017

If we are to have more frequent and extreme rural fires, then Scion is meeting the challenge to provide the advanced science, technology and management to fight them.

Nature has thrown New Zealand a few curve balls lately. Hot on the heels of the Kaikōura earthquake, fires have raged this past summer in Coromandel, Hawkes Bay and Canterbury. They have destroyed homes, farms and forests, as well as damaging vital infrastructure.

Rural wildfires are common in New Zealand. On average, 3000 fires are reported every year and around 6000 ha of land is burnt.

Firefighters anticipate how these fires will develop using tools for New Zealand conditions developed and adapted by Scion’s rural fire research group.

One such tool is called Prometheus. It was used against the Port Hills fire to predict how the fire would behave, including breakout scenarios, how fast it would spread, how hot it would get and how far the flames might reach.

From this, the incident management team developed the fire attack strategies, determined what resources they needed, and how to ensure fire-fighter and public safety, including timing of lifting evacuation cordons.

Scion fire scientist Grant Pearce observed the recent Port Hills fire personally. He says it met the definition of an extreme fire. It escalated suddenly, spread rapidly and with high intensity, changed directions abruptly, with fire whirls and a fire tornado.”

Extreme fires are likely to be more frequent in New Zealand. Climate change is predicted to bring higher temperatures, decreased rainfall in some areas, and stronger, more frequent, westerly winds. More people moving to live in rural areas is also likely to increase the risk of destructive fires.

The Scion rural fire research group has the background experience to meet these threats. Just this month the group and rural fire end-users celebrated 25 years of rural fire research in New Zealand.

Grant Pearce says over these years Scion research has been a mix of reducing fire risk, getting ready to respond and fight fires and how to recover from them.

“Now we are preparing for a future with more extreme fires. We can’t stop Mother Nature, but we can take precautions and be prepared, based on the best science which becomes available. To this end, we began a five-year project to understand and address the threat of extreme fire a few months ago.”

The work is supported by the Ministry of Business, Innovation and Employment’s Endeavour Fund, a number of stakeholders, and Scion’s core funding. Local and international fire experts got together in Christchurch in late February, coincidentally a week after the Port Hills fire, to plan the new research programme.

One of the five research themes is to improve fire prediction tools by gathering information on when extreme fires are likely to occur, what atmospheric conditions cause a fire to escalate, and the affects of heat transfer mechanisms in different fuel types.

The researchers hypothesis is that atmospheric turbulence and convective heat transfer from the flame front to unburned fuels. This is now playing a more important role in fire spread.

The Scion team plans experimental burns to look at what is happening on a small scale within the flame front itself, as well as on the larger scale in the atmosphere above the fire or potential fire.

The researchers plan to use drones, wind sensors, and high-speed and infrared cameras, to record how fire spreads from one fuel source within the fire to another.

The rural fire research group is also working with the Resilience to Nature’s Challenges, National Science Challenge to strengthen how a community copes with wildfires and other natural hazards, improve firefighters’ ability to cope with stress and keep them out of harm’s way with more remote firefighting, and increase the use of drones to monitor fires and hotspots.