This is the County Fire. This north California's wildfire started June 3 and by July 2 spread to nearly 60,000 acres, or nearly twice the size of Singapore. More than 2,115 crews are battling the blaze in three counties - Yolo, Napa and Lake. As of July 2, about 60 wildfires burned throughout the U.S. Wildfire acreage in the US is up 25 per cent. Major wildfires occur throughout the summer due to heat, dry conditions and millions of dead trees that provide added fuel for large blazes. In 2017, the US spent nearly $4 billion fighting wildfires.