Two large grass fires were reported in west Miami-Dade Monday.
Both fires were reported north of Tamiami Trail and west of the Metro-West Detention Center.
Miami-Dade Fire Rescue said approximately 520 acres were consumed by the two fires, which burned simultaneously.
Footage showed heavy smoke and flames at one scene, in the area of the 14000 block of Northwest 41st Street.
"We believe it was lightning because the way the fires kind of originated and the proximity to each other," said Scott Petrich with the Florida Division of Forestry.
Mother Nature was to blame for the hundreds of acres of wildfire, and she'll also determine what happens overnight into Tuesday morning.
"It's a function of how much fuel is out there. Relative humidity and the wind speed," Petrich said.
This fire's fuel was grass and there was a lot of it. As the humidity goes up, the burn subsides.
The Florida Division of Forestry named both fires: The north blaze was Bumpy and the south blaze was Substation. Bumpy was the bigger fire and was 40 percent contained on Monday.
"It grew from 350 acres, when we got a call at 3:30 this afternoon, up until 422 acres," Petrich said.
Substation was only 100 acres and 45 percent contained.
Firefighters had to abandon their efforts to contain the fires when a storm popped up, "The vehicles that they operate on are pure metal and they're very conductive for electricity and lightning."
No structures were threatened.