Drones provide added dimension to monitoring experimental burns

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Scion and the University of Canterbury’s UAV teams were on hand to help during the Rural Fire Research team’s recent gorse burn experiments at Rakaia Gorge in March.

There were up to five craft in the air at once monitoring different aspects of the burns. The spread and temperatures of each fire were tracked using infrared and regular RGB video cameras mounted on a UAV flying above each burn at altitudes up to ~1000 feet (300 m). This footage (see examples below) provides exciting new insights into the convective fire spread theory being tested in these experiments.

The regular visual video (see below) shows streams of smoke separated by clear air that support the theory of inflows of air into the flame front from behind. Areas of updraft, and especially downdrafts and outbursts of flame, can also be seen across the flame front in the infra-red video (also see below). This further supports the theory that the movement hot and cool parcels of air (convection) creates the peaks and troughs observed in the flame front. The figure below is an hypothesised schematic of the physics dominating forward spread of the fire front.

Covective theory graphic (ex Finney et al-PNAS)_LI                                                 [Source, Finney et al. 2015, PNAS 112(32)]

The detailed spatial information on fire behaviour obtained from the aerial videos supplement the data collected from sensors on the ground. These ground sensors include thermocouple arrays, radiant heat flux and pressure sensors purpose-designed for the experiments by the US Forest Service team from the Missoula Fire Lab. Infra-red imagery from UAVs at lower altitudes above and oblique to the flame front is also being used by the University of Canterbury team to track the movement of the hot air parcels ahead of the fire front. UAVs also monitored wind speeds above the burns and within the smoke column, to support observations made by the San Jose State University’s ground-based scanning lidar and to provide information on winds high above the fire.

Drones were also used prior to the burns to fly the site with high definition cameras and lidar to provide high resolution maps and three-dimensional models of the site. This information was used for planning the operations, including siting equipment and producing site maps for firefighters. Drone-mounted aerial lidar is also being investigated for use in capturing fuel properties such as fuel particle sizes and arrangement, as well as estimating fuel loadings.

The new information provided by the UAV observations adds an exciting new dimension to the data collected during the burn experiments, and they will be used again during the next phase of the research with wilding pine crown fires.

Short snippets from Rakaia gorse burn visual (left) and infra-red (right) video. Both are from a UAV centred above the burn plot with the camera looking straight down.
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Gorse experimental burns successful

IMG_2184 (Credit: D. Geddes, FENZ)

As reported in a previous blog, Scion’s fire team along with its research collaborators from the US Forest Service, San Jose State University and the University of Canterbury, and staff and volunteer firefighters from Fire Emergency New Zealand, Department of Conservation and local communtiy, was able to complete a series of burns in gorse scrub fuels in the Rakaia Gorge in Canterbury in early March.

The gorse burns were the second phase of experiments to test the convective fire spread theory, following the completion of crop stubble burns in 2018 and 2019.

Six 4 ha research burns were successfully conducted over three burn days from March 2 to 9, with the research team being able to capture data in high and low wind conditions.

Each burn block contained a myriad of instrumentation, ensuring these were some of the most heavily instrumented experimental fires conducted to date. This included 30m tall towers carrying sensors to monitor wind turbulence and the vertical temperature profile within and above the spreading flame front, as well as loggers across the burn area to record rates of fire spread, heat transfer and flame size. Each burn was also monitored with in excess of $1 million of specialist high-speed visual and infra-red cameras on the ground, inside the fires, and monitoring the fire’s progress from above on unmanned aerial vehicles.

With heavy fuel loadings, gorse is known to burn hot. But the temperatures in the research burns surprised even experienced members of the research team. An infra-red camera on a drone above the burn burns reached the upper limit of its sensing capabilities at around 940°C. In-fire 360° cameras blistered as the water that was supposed to keep them cool boiled off, and data loggers melted inside well-insulated housings. Temperatures in the centre of the fires were recorded to reach almost 1,500°C.

The burns were highly successful, and the research team is now analysing the terabytes of data and video footage from the burns ahead of beginning preparations for the next phase of burns in standing wilding pines.

The burns also generated plenty of media attention, featuring on TV3’s Newshub, in the Otago Daily Times (including The South Today video), and in the local Ashburton Courier newspaper and online edition.

(Credit: USFS)
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April seasonal fire climate outlooks now available

SI outlook

The April 2020 seasonal fire danger outlooks have just been produced, with the outlooks now available for each of the North and South Islands for the April – June period.

These outlooks provide a heads-up on how fire danger conditions are tracking in different parts of the country as we transition through autumn.

The outlooks indicate that while the change of seasons means fire danger levels are declining in some areas, the risk of wildfires remains high in other regions due to continued drought conditions. Areas to keep an eye on for elevated fire risk include: the Far North, Auckland, Coromandel, Hawkes Bay and parts of coastal Manawatu-Whanganui in the North Island; and Nelson, Marlborough, Canterbury and central Otago in the South Island.

Over the next three months, air pressure is expected to be lower than normal, with the country being exposed to westerly air flows, fronts and temperature changes. Temperatures are likely to be above average or near average for most of New Zealand. Cold snaps and frosts are also likely to occur as we move into winter. Rainfall is most likely to be near normal or below normal in the north and east of both islands, and near normal or above normal for western areas.

For those wanting to better understand current conditions in their patch, graphs comparing fire dangers (DC, BUI and CDSR) for individual weather station locations are also available.

Hokianga_DC  NI map w-caption

 

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Paper published on weather conditions associated with the 2017 Port Hills wildfire

Rebuild Chch_d72bdf66a10ece7f(Photo credit: Rebuild Christchurch)

Scion rural fire research team members, with the help of collaborators at the University of Canterbury, recently published an article entitled: “A Meteorological Study of the Port Hills Fire, Christchurch, New Zealand”, in the Journal of Applied Meteorology and Climatology. The article explores the influence of weather on the occurrence of unexpected and unusual fire behaviour during the Port Hills wildfire.

The Port Hills Fire occurred as two separate fires on 13 February 2017 in the Port Hills just south of Christchurch. These fires joined two days later into a major wildfire that was record-breaking for New Zealand in terms of property loss, the threat to infrastructure, scale of evacuation, and smoke impact on the urban population. The main fire activity lasted until the early morning of 16 February. The combined fires (collectively referred to as the Port Hills Fire) covered a total area of 1661 ha, with a final perimeter of 61 km and it took 66 days for the fire to be declared completely extinguished.

The unusual fire behaviour included two fast downhill fire spread events and highly active fire behaviour evidenced by the formation of a large pyrocumulus plume. Fast downhill fire spread poses a risk to the safety of firefighters as it is generally assumed that fires spread faster uphill than downhill. Firefighting often takes place downhill from a fire in complex terrain, as it is considered safer. Rapid downhill fire runs can take firefighters by surprise and put them in danger and it is therefore important to understand the weather that can cause this behaviour, which is what this study aims to do.

The full article can be accessed here.

Previous papers on the Port Hills wildfire by members of the Scion fire team also formed part of a special issue of the Australasian Journal of Disaster and Trauma Studies published in 2018.

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Gorse research burns underway

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After more than 18 months preparation, the first of the research burns in gorse scrub fuels have been successfully conducted. The burns are the second phase of experiments to test the convective fire spread theory, following the completion of crop stubble burns in 2018 and 2019.

The project is a collaboration between the Scion Rural Fire Research team, the US Forest Service’s Missoula Fire Lab, San Jose State University and the University of Canterbury’s Geography Dept. The research burns are some of the most instrumented fire experiments conducted, with a huge range of sensors, cameras and drones recording everything from weather conditions and atmospheric turbulence to fire spread, and in-fire flame front dynamics to lidar tracking of smoke.

The gorse burn site is located near Rakaia Gorge, and comprises six 4 ha (200x200m) burn blocks within an area of 80 ha of riverside gorse. The research burn blocks are surrounded by firebreaks, along with buffer blocks which were burnt out in the days prior to research burns commencing.

The first two burn blocks were successfully completed on Monday (2nd March) on downvalley nor’west winds, with the next burns planned for Friday (6th March) likely under upvalley easterly winds.

The research team is extremely grateful for the significant support received from Fire and Emergency New Zealand and the Department of Conservation with the planning and conduct of both the burnouts and research burns, and especially to the volunteer crews that have provided suppression support. These research burns wouldn’t be possible without that support.

The burns also featured on TV3’s Newshub 6pm News.

More information on the burns can be found here, including a series of Q&A’s on why the burns are being conducted and what precautions are being put in place.

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Scion smoke model predicts more Aus bushfire smoke for NZ

BSF Aus smoke

Scion has continued its development of the New Zealand BlueSky Framework smoke forecasting model.

In the latest runs, it predicts smoke from the Australia bushfires to impact NZ again over the next few days.

The purpose of the NZ BlueSky Framework is to warn people of smoke concentrations reaching harmful levels during wildfires or prescribed burns. The Framework is currently in its Beta version (meaning that it is still undergoing finetuning for the NZ environment), but it has already successfully been used during the Pigeon Valley wildfires in the Nelson region in February 2019, and now, during the Australian bushfires.

The figure above shows the Australian bushfire smoke predicted to impact NZ on 4 February at midday. The Google Earth animation below of the model’s output shows the smoke is forecasted to reach NZ intermittently over the next four days.

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Fire researchers on RNZ’s ‘Our Changing World’

eight_col_000_1ND4XF(Photo credit: AFP)

Members of Scion’s rural fire research team recently appeared on Radio NZ’s Our Changing World, speaking about the increasing frequency and severity of wildfires and how many NZers are underprepared.

Scion’s Lisa Langer, Grant Pearce and Tara Strand were interviewed along with Mel Mark-Shadbolt from Te Tira Whakamātaki (the Māori Biosecurity Network).

See more details on the programme and listen to the full panel interview here.

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Funding for fire climate change research translation

closeburn-jamie-cowans-photo3.jpgPhoto: Homes amongst wilding trees in the Queenstown Red Zone (Credit: Jamie Cowan).

Scion was successful recently with a proposal to the Ministry for Primary Industry’s Sustainable Land Management and Climate Change (SLMACC) funding round.

The aim of this 18-month project is to enhance preparedness of New Zealand rural land owners, rural-interface communities and related agencies for future extreme fires by applying a physical climate science driven threat assessment to location-specific societal adaptation and mitigation best practice.

The project will utilise results from the latest wildfire risk climate change simulations being undertaken by Scion and research into landowners’ risk perception and preparedness for wildfires as well as other hazards. This will inform the co-design of guidelines with Fire and Emergency New Zealand for promoting individual landowner and community planning and actions to mitigate the identified risk of increased wildfires with climate change. The project will be based around a case study in the Queenstown Red Zone.

Ultimately, outcomes from the project will lead to better prepared and more aware government agencies, councils, landowners and residents living in high wildfire risk areas with improved access to appropriate adaption and mitigation practices.

For more information on the project, contact Lisa Langer.

             Photos: Homes in the Queenstown Red Zone threatened by the 2005 Closeburn wildfire                            (Credit: Jamie Cowan).

Workflow infographic

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Funding for kāuta design project

Scion, in partnership with the Tau Iho I Te Po Trust, were recently successful in obtaining Vision Mātauranga funding.

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The 3-year project, entitled “Kāuta: He hononga mo te tangata manaaki” (Traditional hearths: Bringing people together), is about creating engagement as scientists, tangata Māori and regulatory agencies come together to develop specifications for a modern kāuta (open, internal/external fireplaces used for cooking and heating).

Manaaki ki te tangata (hosting and taking care of people) is central to Māori culture and society, and marae kāuta have featured at the heart of this tradition. However, modern regulations surrounding open fires have contributed to the decline of kāuta, and in the process many kāuta have been decommissioned and the culture and mātauranga associated with kāuta are being lost.

This mātauranga Māori project uses the development of kāuta specifications that meet cultural and regulatory standards as a focus for engagement between Māori, scientists and regulatory agencies. This will result in skills transfer in product development, with scientists and agency personnel experiencing tikanga Māori and building their cultural capability whilst engaging Māori in research with scientists and product developers. The project team will ensure cultural significance through extensive Māori engagement, including social media.

The project will produce a set of specifications that will be used to inform future co-design, development and testing of alternative, contemporary kāuta that meet traditional, cultural and regulatory needs. It is hoped that the reinstatement of kāuta in marae will assure a place for inter-generational sharing of mātauranga Māori and help support the retention of intergenerational whanau and Hapū traditions, culture and identity.

For more information on the project, contact the research team.

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January seasonal fire climate outlooks available

NI-Jan2020

The January 2020 seasonal fire danger outlooks have been produced, with the outlooks for each of the North and South Islands for January – March now available.

These provide a heads-up on how fire danger conditions are tracking in different parts of the country as we transition through summer.

The outlooks indicate increasing fire danger levels in many parts of the country as a result of warmer, drier conditions and drying soils. Cooler than average temperatures are expected to start the month of January, with more moderate temperatures forecast thereafter. Near normal rainfall totals are forecast, being a touch drier than average with the presence of high pressure systems. There is also the chance of spells of hot weather for New Zealand with warm Australian air masses anticipated to cross the Tasman Sea occasionally during the next month.

Vegetation and soil moisture levels over the summer months will continue to be affected by warm temperatures, low rainfall and strong gusty winds. This will result in the medium to heavy fuels continuing to dry out, elevating the fire risk and contributing to potential for deeper burning and faster moving fires.

Areas to keep an eye on for elevated fire risk include: Northland, Auckland, Waikato, Gisborne, Hawkes Bay, Manawatu-Whanganui and Wairarapa in the North Island; and Nelson, Marlborough, Kaikoura, North and South Canterbury, and Otago in the South Island.

For those wanting to do further analysis, additional graphs comparing fire dangers (DC, BUI and CDSR) for each weather station are also available.

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