The past week has seen an outbreak of new fire hashtags in Northern California, and that pattern doesn’t seem to be stopping anytime soon. KTLA sister station KRON spoke with fire expert Jon Keeley, a research scientist for U.S. Geological Survey, about why we’re seeing so many fires and what we can do to protect ourselves and our homes.

“The one correlation we find with a lot of fire activity is drought. This is not a recent phenomenon,” Keeley said.

Drought means there’s less moisture in the grass and woodlands to combat small ignitions. This lack of moisture turns grass, trees, and other vegetation that has the capacity to burn into “fuels” for fire. Though we’ve seen drought conditions on and off for nearly 20 years in California, Keeley says that our current drought state is not indicative of future droughts, it’s just what we’re faced with right now.

But the biggest concern when it comes to fires isn’t drought, it’s people, “at least 95% of the fires in our area are started by people.” That number might seem high for us in northern California, but it isn’t the highest in the state. According to Keeley’s article, “Historical patterns of wildfire ignition sources in California ecosystems” published in the International Journal of Wildland Fire, many areas of southern California see closer to 99% of their fires ignited by people.

Keeley says that the fast population growth we’ve experienced in California over the last few decades could be a contributing factor, “urban sprawl has pushed people out into these landscapes where they are more vulnerable,” he said. More people in more places means a higher likelihood of fire, especially in a drought year.

What are some of the activities that risk fire? This time of year fireworks become a big concern, which is partly why they are illegal. Keeley’s paper found that most fires are caused by, “equipment, arson, debris burning, children playing with fire, smoking, vehicles and powerlines.”

People who live in or near the Wildland Urban Interface (WUI) have to be especially aware of fire risk at this time of year, “it’s your responsibility to do whatever you can to reduce fires from impacting your house,” said Keeley. Most homes burn from embers that land on the house, he added.

One way to potentially mitigate the risk from embers is encouraging moist trees like cedars or oaks to grow around your home, “There’s some evidence that trees pay a beneficial role in blocking embers from landing on homes, but this is a hypothesis,” Keeley says. However, not all trees are equal in this regard. Keeley tells KRON that pine trees have a lot of “dead fuel retained in the canopy,” which could later ignite, and they may not be a very effective blocker.