As more people build houses on the fringes of wooded areas, the approach to firefighting is getting more complex 鈥� and the out-of-control wildfire near Halifax is one stark example, experts say.

The fast-moving wildfire that broke out Sunday destroyed an estimated 150 homes and forced about 16,000 people from their homes in subdivisions northwest of Halifax.

Roger Collet, wildfire management officer with the New Brunswick Department of Natural Resources, said such 鈥渋nterface鈥� fires require teams from municipal fire departments to work alongside wildland firefighters.

鈥淲here the forest meets the urban area 鈥� the subdivisions where people are living in there 鈥� it鈥檚 still quite wooded, so we have to work together,鈥� he said in an interview.

Robert Gray, a wildland fire ecologist in British Columbia, said whether a fire is in an urban or wildland setting, one of the first things firefighters do is establish a containment zone.

In forested areas, he said, firefighters put down a fire break around the boundaries of the blaze to keep it from spreading further. This is usually done by bulldozing up mineral soil or pouring a combination of water and retardant out of a helicopter, he said.

鈥淎ll you can do to stop the fires is rob it of energy, of fuel,鈥� he said.

While in forested land the interior of a fire is often allowed to burn itself out, in an urban setting the main aim is to stop it from spreading to structures, Gray said.

鈥淵ou don鈥檛 want what鈥檚 called an urban conflagration, which is multiple houses burning at once,鈥� he said.

Dave Steeves, a forest resources technician with Nova Scotia鈥檚 Department of Natural Resources, said firefighters are following a direct and indirect approach to attack the Halifax wildfire.

鈥淭he direct attack 鈥� is where we鈥檙e spraying water directly on a fire,鈥� he told reporters. 鈥淚ndirect attack 鈥� is where we are removing vegetation from an approaching fire.鈥� The purpose of removing vegetation and creating a perimeter is to starve the fire of fuel, he told reporters this week.

鈥淚f the intensity levels are low enough, when it burns up to that break, it will have nowhere to go and it will it will snuff itself out.鈥�

He noted that while traditional firefighting in forests would first involve establishing a containment line, that approach wasn鈥檛 well-suited to the Halifax fire.

鈥淭his situation was so different with the amount of structures that were involved, that it was difficult to take a traditional approach to it,鈥� he said. 鈥淲e had to focus on the structures of value first, before we could actually work on the containment.鈥�

Blazes that experts have said are examples of interface fires include the Fort McMurray and Slave Lake, Alta., infernos where homes were built on the edge of woods. The 2011 Slave Lake fire destroyed more than 400 homes and the 2016 Fort McMurray wildfire destroyed more than 2,400.

Gray said one of the most important priorities when confronting an interface fire is to prevent as many structures as possible from burning down, while watching out for the many threats firefighters face in urban areas such as downed power lines, vehicles and all that goes into making everyday life.

鈥淗omes burn differently than the woods do,鈥� he said. 鈥淚t can be quite hazardous for firefighters.鈥� The chemicals in the air are different because they involve compounds released from the combustion of manufactured goods, he said.

鈥淲e don鈥檛 wear breathing apparatus on wildland fires, although we may have to in the future,鈥� Gray said. 鈥淲e鈥檙e dealing with very different smoke and smoke constituents. It鈥檚 the makeup of the smoke that can be very, very dangerous in an urban setting, especially if there鈥檚 high winds, and there鈥檚 lots of structures involved at one time.鈥�

Collet said the hazards are the biggest difference between fighting wildfires on forested land versus in urban areas.

Damaged homes that can fall on firefighters, vehicles that explode, downed power lines and weakened trees are just some of the hazards firefighters have to navigate in urban settings, he said.

鈥淭he wilderness is a little bit different, because it鈥檚 mostly just trees,鈥� Collet said. 鈥淲hat we鈥檙e doing is we anchor from a safe place, and we start fighting the fire 鈥� working that way. There may be a little more risk when you鈥檙e trying to save somebody鈥檚 house. But again, the training is different. And the structure firefighting is done by fire departments.鈥�

Training for firefighters in urban areas is different compared with those in forested areas, Gray said, although some rural communities offer cross-training.

鈥淐ommunities that have both kinds of fires, they do cross-training,鈥� he said. 鈥淭hey鈥檙e taught to deal with both structure fire and wildfires. There鈥檚 actually a course for wildland firefighters working in the interface. It deals with things like hazardous materials and electricity and things like that.鈥�

Hina Alam, The Canadian Press

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