About 2,000 firefighters are battling wildfires in Kansas that have consumed more than 1,000 square miles.

State Department of Emergency Management spokeswoman Katie Horner says the number of helicopters dumping water on the fires will increase Wednesday from six to nine. This is possible because flying conditions are safer due to calmer winds.

More than half of the blaze has burned in Clark and Comanche counties, both ranching and farming communities along the state’s southern border with Oklahoma. Horner says she can’t yet provide a cost estimate of the fire damage.

The most populated area affected is Reno County, where 10,000 to 12,000 people voluntarily evacuated their homes Monday. By Wednesday, 1,000 to 2,000 residents of the county remained displaced.