Johannesburg’s OR Tambo International Airport was forced to close one of its runways after dry grass caught fire and “spilled over from the adjacent community within the airport precinct,” it said via Twitter.

Fire and rescue teams are onsite to extinguish the blaze, according to OR Tambo, which is the busiest airport in Africa.

The runway that has been closed is typically used for landings because it’s long, at more than 4.4 kilometers (2.7 miles), which helps planes land in the thinner air at Johannesburg’s relatively high altitude, aviation society Scramble said on its website.

In Johannesburg and surrounds it’s the end of a dry winter and there are frequent fires until the rains arrive, usually in October.