Firefighters in North and South Carolina were battling multiple wind-driven wildfires Monday in rugged terrain that complicated containment efforts, officials said.

Millions of trees knocked down by Hurricane Helene last year combined with long stretches of dry weather this spring are making for a long and active fire season in the Carolinas, North Carolina State University forestry and environmental resources professor Robert Scheller said.

“Helene just dropped tons of fuel on the ground,” Scheller said. “Then these flash droughts allow that fuel to dry out very fast.”

Both South Carolina and North Carolina have issued statewide bans on outdoor burning.

Mandatory evacuations continue for about 165 properties in parts of Polk County in western North Carolina, about 80 miles west of Charlotte, according to county spokesperson Kellie Cannon.

Three fires burned at least 7.5 square miles in the county and the two larger blazes were completely uncontained, Cannon said in a social media update Monday morning. The Black Cove Fire, one of the larger ones, was moving toward neighboring Henderson County, Cannon said.

A downed power line sparked the Black Cove Fire, but the causes of the other two fires in Polk County were under investigation, according to North Carolina Forest Service spokesperson Jeremy Waldrop.

A number of other wildfires burning across the state including one that damaged 500 vehicles at a salvage yard in Burke County, officials said.

Two fires in the South Carolina mountains have led Gov. Henry McMaster to declare a state of emergency.

One fire was in Table Rock State Park in Pickens County and the other was on Persimmon Ridge in Greenville County. Winds and difficult mountainous terrain allowed blazes to grow, the South Carolina Forestry Commission said.

The Table Rock Fire expanded to more than 2 square miles, including several hundred acres that firefighters intentionally burned to try to contain the flames, officials said.

The Persimmon Ridge Fire, which started Saturday, spread to more than 1.25 square miles despite many dozens of water drops, the commission said.

Human activity ignited both the Table Rock and Persimmon Ridge fires. No injuries had been reported, and while no structures were imminently threatened, voluntary evacuations of about 100 homes remained in place.

Scheller, the North Carolina State University professor, predicted this busy fire season if the region saw dry weather following Helene.