California’s climate has always been hospitable to fire – it comes with the territory. But add five years of drought and rising temperatures, and it’s a recipe for disaster.

“We are seeing the compounded effects of climate change that includes five consecutive years of drought and rising mean temperatures across the West – last year was the hottest year on record,” said Janet Upton, deputy director of communication at the California Department of Forestry and Fire Protection (Cal Fire). “All that is trending to a more flammable California.”

Last week the U.S. Forest Service reported that 26 million trees had died in six counties in the southern Sierra Nevada since October. Adding in an estimated 40 million dead trees counted since October 2010, it brings the statewide tree mortality to at least 66 million in less than six years.

High rates of tree mortality are being driven by bark beetles in combination with the state’s drought. Like fire, bark beetles are a natural part of the state’s ecology and a way for nature to weed out the weak and keep forests healthy. But when the trees suffer from drought, they no longer have their natural defense mechanism to fight off bark beetles. “Trees draw up moisture and push the beetle out,” said Upton. “With the drought, they couldn’t draw the moisture needed to do that.” And that has led to a bark beetle explosion – to epidemic levels.

Hardest hit so far has been the southern Sierra. “We identified six high hazard counties and now we’ve added four more,” said Upton. The bark beetle blight is marching to the north.

“It’s a slow-moving disaster, I can’t characterize it any other way,” she said. “It’s heart-wrenching. These residents moved there to enjoy a beautiful, natural forested landscape and it’s dying before their eyes.”

Jimmy Romo, 73, leads a horse and other animals from his ranch as a wildfire burns behind them in Azusa, Calif., on Monday, June 20, 2016. Police in the city of Azusa and parts of Duarte ordered hundreds of homes evacuated. (Ringo H.W. Chiu, AP)

While this fire season may be shaping up to be a bad one, it is also part of a growing trend. Of the top 20 largest fires by acreage in California’s history dating back to the 1920s, half have occurred since 2002, said Upton. And fire intensity is increasing, too. The kind of fires we are seeing more of now, said Upton, are not the “good” fires that help restore natural landscapes, but devastating ones that burn everything in their path, causing mudslides and damage to water supply.

“Vegetation thrives on fire, but it thrives on healthy beneficial, low-intensity fire,” said Upton. “Not these fires that absolutely convert a forest into a brush patch.”

Even the parts of the state that got near-average rainfall this year have seen it’s been a double-edged sword. In many places rain fueled a robust crop of annual grasses, which have died out and are now the perfect kindling for an errant spark.

Wildfires are a danger to health, safety and property, but they also can impact crucial watersheds, which feed urban water supply. “People in urban areas don’t necessarily think about where the [water in the] faucet originates and how important a healthy forest is to a clean, reliable water supply,” said Upton.

State agencies are prepared for the fire season, though, Upton said – thanks in part to the governor’s budget, which has included $77 million extra to staff up early. This preparation has included hiring 400 seasonal firefighters in February and adding extra engines, extra aircraft, extra support personnel and even extra public educators.

Cal Fire has launched a website for its “Ready, Set, Go!” campaign to help the public learn what to do before, during and after a wildfire. “Literally this information can be lifesaving,” said Upton. “We urge residents to get on that website.”

She says the long-range goal is to create a healthy forest in California that will be better able to fend off bark beetles and disease infestations and can withstand fire a lot better.

But there is a long way to go before then and more resources are needed. Last year was the first year that the Forest Service had to spend more than 50 percent of its budget on fire suppression (compared to just 16 percent in 1995), which leaves less money for restoration and management projects to increase forest health and restore watersheds.

“Unfortunately, unless Congress acts now to address how we pay for firefighting, the Forest Service will not have the resources necessary to address the forest die-off and restore our forests,” said Agriculture Secretary Tom Vilsack. “Forcing the Forest Service to pay for massive wildfire disasters out of its pre-existing fixed budget instead of from an emergency fund like all other natural disasters means there is not enough money left to do the very work that would help restore these high-mortality areas. We must fund wildfire suppression like other natural disasters in the country.”