Two wind-whipped grassland fires in rural southeastern Colorado destroyed two homes, briefly closed a state highway and forced temporary evacuations in the unincorporated community of Fort Lyon, fire officials said.

The fires erupted Tuesday west and east of the town of Las Animas and had blackened nearly 8 square miles by Wednesday, according to the Bent County Office of Emergency Management.

Crews had contained 10% of a fire that began near Bent’s Old Fort National Historical Site. The site itself wasn’t damaged, KKTV-TV reported. A second fire east of Las Animas briefly forced evacuations near Fort Lyon. Crews from around the state were working the blazes.

Two homes were destroyed, officials said, and a section of state Highway 50, the area’s main thourifare, was briefly closed. Colorado Parks and Wildlife reported that 75% of the Oxbow State Wildlife Area east of Las Animas had been blackened, and the agency closed the John Martin Reservoir State Wildlife Area as a precaution.

The cause of the fires was unknown.

The Associated Press