HOW DROUGHT IS DRIVING WILDFIRES

As our planet heats up and dries out, prolonged periods of drought are turning plants into kindling and creating just the right conditions for fires to ignite and spread. Drought and wildfires go hand in hand: it’s a vicious cycle sure to grow worse as global warming continues.

During a drought, the moisture in the soil decreases, and plants become dehydrated. We’ve all seen what happens if we forget to water the houseplants for a few weeks. In the wild, as trees, shrubs, grasses, and leaves dry out, they become highly flammable fuel. Dry vegetation acts as tinder, making it much easier for fires to spread fast, especially when burning leaves and twigs get kicked up in the wind. And without moist vegetation to slow or dampen a fire, fires become more intense and way more difficult to control.

Drought weakens trees, making them more susceptible to disease, insect infestations, and death. When large numbers of trees die, the dry wood becomes highly combustible fuel. This is especially evident in places like California, where millions of trees have died from drought and bark beetle infestations. These dead trees make it easy for fires to consume large swaths of forest.

Places prone to drought usually have strong winds as well as we saw in the LA fires this January. Winds carry embers great distances, miles even, starting new fires far from their original source. When the landscape is especially dry, these embers are more likely to ignite new fires, turning 10 small fires into 1 enormous one, capable of devouring a town in days. Wind-driven fires are among the most dangerous and destructive because they move quickly and unpredictably, outpacing firefighting efforts.

Droughts are often accompanied by higher-than-average temperatures, which creates a perfect environment for fires to thrive. High temperatures dry out plants and soil, fueling the fire – so once a fire starts, it’s more likely to spread. Meanwhile high temps come with low humidity, i.e. less moisture in the air, so it takes much more water to put out a fire.

Drought primes the landscape to burn. A discarded cigarette, unattended campfire, or sparks from a car or machine can ignite a large fire – and fast. This kind of human carelessness in hiking areas and campgrounds is still one of the biggest causes of wildfires. That’s why we increasingly have burn bans in states with intense, hot summers.

Taken together, all of these are why droughts also make for worse fire seasons. Wildfires used to strike in late summer and early fall, but now they’re starting earlier and going later. Across the West, fire season is 2-3 months longer than a few decades ago and it’s nearly year-round in parts of California. With droughts, it’s easier for wildfires to ignite and spiral out of control. Slowing climate change is the only way to reverse the cycle.