On a ridge overlooking the foothills of the Sierra Nevada Mountains, it would have been possible to see the first flickering flames of the Oak Fire and then how it engulfed its surroundings.

It took just 24 hours to mushroom to 10,000 acres and become California’s biggest wildfire this year.

“That’s crazy fast,” said Joe Amador, one of thousands of firefighters from across the state now deployed to fight the blaze.