Is it unusual to see such fires in California at this time of year?
Fires break out frequently in this region, but rarely in January. “When this is the case, they are normally smaller fires that have little impact,” explains Professor Mike Flannigan of Thompson-Rivers University, a specialist in forest fires.
According to experts, these exceptional fires can be explained by the combination of different parameters: an autumn which was extremely dry, preceded by two winters which, conversely, were particularly humid – so that there were many vegetation likely to burn.
And although it is common for this region to be swept by strong, hot and dry winds – the “Santa Ana winds” – those which are blowing at the moment are of rare violence. Gusts of up to 160 km/h have been reported.
“These are incredibly violent winds,” says Marc-André Parisien, a researcher with the Canadian Forest Service in Edmonton, Alberta.
These gusts could also have caused trees to fall on power lines, which could be a trigger for the fires, says Mike Flannigan.
PHOTO MARK ABRAMSON, THE NEW YORK TIMES
Los Angeles residence ravaged by flames
In short, “all the factors are there for several fires to break out at the same time,” he adds.
This simultaneity and speed make these fires very difficult to fight on all fronts at once – especially since they broke out near inhabited areas.
“It’s really this speed that’s impressive, and the number of structures affected, rather than the total area that was burned,” says Karen Hodges, professor of biology at the University of British Columbia and specialist in forest fires. .
What is the contribution of climate change?
It is still too early to attribute this particular event to climate change.
But in general, we have observed, for several decades, that forest fires tend to become more frequent and more devastating – in California, but also elsewhere in the world in general, recalls Karen Hodges.
“With climate change, we expect to have longer and drier fire seasons,” she emphasizes.
“The hotter and drier it is, the greater the probability that a fire will break out and spread,” adds Marc-André Parisien.
What can be done to avoid such disasters in the future?
There are solutions to try to combat these catastrophic events, in the more or less long term.
“We must of course accelerate the fight against climate change,” responds Karen Hodges straight away.
Limiting urban sprawl could also make it possible to have homes less close to vegetation likely to catch fire, which would limit the impact of these fires on populations.
“Around Los Angeles, wild and urban areas coexist. And it is one of the most flammable vegetations in North America, recalls Marc-André Parisien. It really is the worst of both worlds. »
PHOTO FRED GREAVES, REUTERS
Firefighter in action against the Eaton fire, north of Los Angeles
On the part of public authorities, we could also consider burying electrical transmission lines to limit the risks of starting fires or increasing the resources devoted to fighting fires.
In the short term, power could be cut off on certain lines to limit the possibility of a fire breaking out. But for a city like Los Angeles, it is difficult to completely cut off power: certain essential sectors, such as hospitals, must continue to be powered.
On a smaller scale, residents can also try cutting down conifers or clearing branches or dead leaves near their home, following the principles of the FireSmart program.
“But in such windy conditions, people couldn’t do much about these fires,” observes Karen Hodges.
Three ingredients for a forest fire to start
First, there’s vegetation, says Mike Flannigan, a professor at Thompson-Rivers University and an expert on wildfires. Are there a lot of them? Is it particularly dry? Are these plants that burn easily? “These are elements that play a big role,” believes the expert.
Then there are weather conditions that can favor the outbreak and spread of a fire – typically, “a dry, hot and strong wind,” he adds.
Finally, there is the trigger. It can be a natural phenomenon, such as lightning, or man-made – like negligence or power lines coming into contact with trees, for example.
