What began as a 100-acre grass fire Wednesday afternoon in a remote part of San Luis Obispo County has grown to a 35,000-acre blaze in less than 24 hours.

Cal Fire reported Thursday morning that the Madre Fire in San Luis Obispo County had grown to 35,500 acres and was jut 5% contained.

The fire broke out around 1 pm along Highway 166 east of Old Sierra Madre Road, and its origin is under investigation. As the Santa Maria Times reports, an initial estimate put the fire at 100 acres, and some evacuations were ordered. Highway 166 remains closed in the area.

At over 35,000 acres, the Madre Fire is now the largest in the state so far this year, eclipsing the devastating wildfires in Los Angeles in January. However this is burning in a remote area primarily covered with grass, as the Santa Maria Times explains, "driven by wind and local topography." Soon, though, it will "transition into heavier vegetation."

The fire has burned into the Carizo Plain National Monument, and is burning near the northern border of Santa Barbara County.

Hot and dry conditions along with 25-mph winds are expected to aid in the fire's growth on Thursday.

As the Chronicle reports, smoke from the fire is affecting air quality in nearby Santa Barbara County, and the smoke haze is visible from Los Angeles but is not yet affecting air quality there.