THUNDER BAY — Innovative research into the effectiveness of aerial firefighting is helping the Ministry of Natural Resources and its research partners prepare for an anticipated growing threat from wildfires in years to come.
What's being learned by the ministry's Aviation, Forest Fire and Emergency Services Branch will also help inform the strategies of other firefighting services across Canada and around the world.
Since 2017, Northwestern Ontario has been the major research site as the MNR strives to better understand the specific capabilities of its current aerial firefighting aircraft, and what their limits are.
In partnership with the Canadian Forest Service and the University of Toronto, it's been testing the performance of six types of aircraft commonly used in waterbombing operations over the boreal forest:
- Canadair CL-415 (capacity 6,100 litres)
- CL-215 (5,400 litres)
- DHC-6 Twin Otter (2,000 litres)
- AT-802 Fire Boss (3,000 litres)
- Bell 212 helicopter with specialized fire attack system (1,400 litres)
- EC130 hel9i9coter with a Bambi bucket (680 litres)
Tests conducted in the Dryden area saw over 100 water drops made both over open areas and forested stands to compare how much water reaches the ground and to determine the 'drop footprint', which is the area where the water is actually dispersed.
Every aircraft has a distinct drop footprint.
The researchers initially used an established, labour-intensive method: fixing over 500 cups into the ground, then meticulously checking each of them for how much water they contained after a drop.
But they also tested a new remote-sensing method of measuring drop footprints and coverage levels, which incorporates an infrared camera mounted on a tower.
"We did this in an open field. The camera was pointing down at the field, and the air tanker would come and drop, still into the cups, but this IR camera was also measuring the 'coolness' of that drop area," Melanie Wheatley, wildland fire research scientist with the MNR, explained in an interview. "From there, we could process that data to get drop coverage levels."
The remote-sensing technology enabled the team to more precisely determine how much water was being dropped and where it was going, but they still didn't know what the water was actually doing to the fire.
So they then proceeded to develop theoretical, energy-based models of airtanker suppression.
"We can guess for different levels of fire intensity, how much energy is coming off that fire. When we add water to a fire, we're essentially adding negative energy," Wheatley said. "These models say if we know how much energy is coming out of the fire, and how much negative energy is going in, that balance is going to be zero, and that fire is going to be doing virtually nothing, or just smouldering, not flaming anymore."
She said models based on these principles were developed for different types of airtankers, and they are now publicly available in a reference guide published through the Canadian Forest Service.
They can be used by fire management agencies to determine the relative effectiveness of the aircraft, and which model might be the most appropriate for a different job.
Research was conducted over a forest fire in the Sioux Lookout district
Last month, a crucial stage in a project that started seven years ago and was disrupted somewhat by the pandemic took place in the ministry's Sioux Lookout fire management sector.
"We had our drop footprint testing, we had our energy models, but we need to validate the models based on real-world observations," Wheatley said. "The best way to do this, obviously, is to go out to fires and actually measure the effectiveness of airtankers and the impact of drops on fire behaviour."
In collaboration with the National Research Council of Canada, a helicopter equipped with a belly-mounted infrared camera was deployed.
This was a logistically challenging experiment because the chopper – the only one of its kind in the country – was only available for 10 days.
Wheatley recalled, "We were banking on the environment and a lightning strike to give us an ideal candidate fire that was in an ideal field type, that had a uniform, active fire line, so that we could conduct this experiment within that 10-day window, and we lucked out, and that did happen."
The helicopter was flown well above CL-415 airtankers, monitoring their drops and the impact they had on fire behaviour with the IR camera.
At the same time, on a second helicopter, a trained air-attack officer accompanied by research scientists and fire behaviour specialists coordinated all the tanker drops while the team documented its observations of fire behaviour.
"So we would be reporting things like reduction in flame height and spread, percentage of flaming fire line, and discontinuous fireline due to the airtanker drop. We can use those observations to pair with the thermal imagery from the infrared camera," Wheatley said.
That imagery will be processed and analyzed to provide a close look at how the tanker drops impacted the fire spread, fireline intensity and the cycle of water effectiveness.
"Essentially, how long is that fireline gonna hold before you need to come back and put more water on it," Wheatley summarized.
The CL-415 is the workhorse of waterbombing aircraft across the country, but it is also used around the world.
There's more work to be done, but in the shorter term, the information being gathered in these experiments will directly influence how wildfires are managed, including decisions on which aircraft to deploy and how long they will need to be assigned to particular fires.
Wheatley said they will also inform Ontario's long-term strategic planning for the procurement of the next set of airtankers, "and how we are going to fight fire effectively as we deal with the warming climate and resource shortages for the next decade to 50 years."
Globally, most research on the effectiveness of firefighting aircraft has focused on ground-based aircraft that use fire retardants, but this is the first time anywhere that these kinds of experiments have been used to assess the effectiveness of "skimmer" airtankers that scoop water from a lake.
"There are significant resource shortages, aviation shortages, across the world," Wheatley commented. "Knowing how we can use these resources most effectively, knowing that we can pull our airtankers off a fire, that that line is now going to hold and that those tankers can go somewhere else, maximizing their use, will really benefit the fire management community."
She described the ongoing study as being crucial for both daily fire-response decisions and long-term strategic planning, saying it shows how AFFES is at the forefront of applied scientific research aimed at solving real-world fire management challenges.
