Forest fires | The unusual challenge of fires in the forest

A forest fire is not a fire like any other. When the blaze is at its peak, the firefighters do not seek to extinguish it, but to slow its progress and, sometimes, to make it take another path.

When a house burns, firefighters hose down the burning building to fight the fire, not the neighbors’ residences. It’s quite the opposite in the forest, where the best strategy is not to put out the fire, but rather to cut it off so that it eventually goes out.

The objective is not so much to put out the fire as such, but rather to slow its progression, explains Évelyne Thiffault, forest engineer and professor in the department of wood and forest sciences at Laval University. “It’s very different from what an ordinary firefighter does in normal times,” she illustrates.

“Put eyes on the fires”

Condition sine qua non to fight a forest fire: deploy teams in the air not to fight the fire, but to follow its progress in minute detail. Their mission? Supply the teams in charge of fighting against the fire with as much information as possible.

This is the work, among others, of Jonathan Boucher, a researcher from Natural Resources Canada on loan to the Society for the Protection of Forests Against Fire (SOPFEU) to help the teams currently fighting numerous fires in Quebec.

“The objective is to put eyes on the fires”, explains Mr. Boucher in a telephone interview with The Pressduring a rare break on Saturday between two surveillance flights.

Every morning, Jonathan Boucher studies the maps and satellite images. He then flies off to validate the information in the field. Information that is crucial to enable operations to do their job. “Fires that travel a distance of 20 km in one day, we see them now,” he said.

Multiple Strategies

The direction of the winds, their speed, the topography of the area affected, the type of vegetation and the intensity of the fire are all factors that must be taken into consideration when it comes time to fight a forest fire. You should also know that there is not a single method for fighting a fire, but many techniques. “But all means of combat have operational and efficiency limits,” warns Mr. Boucher.

When we think of forest fires, we obviously think of tanker planes that travel the sky releasing large quantities of water on the blaze. But barring heavy rains, there is usually not enough water to put out such fires.

The objective is to reduce the intensity of the fire on its edges. Such a strategy can also help direct the fire, adds Jonathan Boucher.

“As Quebec is a territory with a lot of bodies of water, we use them to fight fires,” says Évelyne Thiffault. The province is recognized in particular for the use of air tankers to fight fires: “We are the best specialists in this technique,” ​​specifies the forest engineer.

To complete the water strategy, teams go to the field, when the fire is less intense, in order to put out as many sources of fire as possible. We also set up fire zones “to break the continuity of the fire”, specifies Jonathan Boucher.

In Chibougamau, for example, the authorities had trenches dug to protect certain sectors of the municipality. Trenches which are not really trenches, however, since the idea is to remove all vegetation to prevent the progression of the fire. Such a trench was dug near Saint-Lambert, south of Normal, in Abitibi. This is a few tens of meters wide and several kilometers long near the municipality.

Fight fire with fire

Another strategy is to fight fire with fire. Less popular in Quebec, this technique is commonly used in France, Spain and the United States. But if the conditions are right, Quebec firefighters sometimes use it, says Évelyne Thiffault. SOPFEU also confirms that its teams are currently using this technique in the field.

“The objective is to reduce the quantity of fuel before the fire arrives”, explains Jonathan Boucher. For example, from a path, we will start a fire to burn the trees and the vegetation in the direction of the fire. “When it arrives, the fire will lose its intensity or perhaps even go out,” says the researcher.

But you need very special conditions to fight fire with fire. Above all, we don’t want to start a fire that we would lose control of. “The type of vegetation must also be taken into consideration,” notes Mr. Boucher.

But faced with a forest fire, all possible techniques can sometimes be in vain if Mother Nature puts in place the worst conditions to promote a fire. However, it can become an ally of choice if the rain gets involved.