Severely dry conditions have caused rampant wildfires across California. Most notably, the Rim Fire burned in and around Yosemite National Park, consumed 400 square miles, and caused over $100 million in damages.

USA Today reported that 98 percent of the state is in a drought: “According to Cal Fire [the California Department of Forestry and Fire Protection], more than 4,700 separate fires have already charred the state this year, which is more than 1,300 fires above average. These numbers are for fires fought by Cal Fire only, and do not include fires that occur on federal land.”

The Rim Fire was the third-largest wildfire in modern California history, according to FOX News. “The wildfire started in the Stanislaus National Forest on Aug. 17 when a hunter’s illegal fire swept out of control and has burned 394 square miles of timber, meadows and sensitive wildlife habitat,” the news outlet reported. It was not fully contained until after September 30.

California may lead the nation in wildfire incidences, but it is not alone. Nationwide, 31,986 wildfires have burned 3.4 million acres this year, according to a press release by the National Interagency Fire Center. Though the numbers represent only 60 percent of the 10-year average, the organization warned that “wildfire activity has escalated…after thunderstorms, many with little or no moisture, moved across parts of California, Oregon, Idaho and Montana, sparking hundreds of new fires.”

Though lightning or, as is often the case, human carelessness can start a wildfire, according to research led by Michigan State University scientists, shifts in climate often cause “larger and more destructive” wildfires in the West.

According to the research cited by ScienceDaily, “Large wildfires are mainly driven by natural factors including the availability of fuel (vegetation), precipitation, wind and the location of lightning strikes. In particular, the researchers found that exceptionally dry and unstable conditions in the earth’s lower atmosphere will continue contributing to ‘erratic and extreme fire behavior.’”