Rising temperatures on Wednesday posed new challenges for firefighters who have made incremental progress against a massive wildfire in central California that injured four people as it became the biggest blaze in the state so far this year.

Temporary evacuation sites were established at Benjamin Foxen Elementary School in Santa Maria and the Cuyama Valley Family Resource Center in New Cuyama, Cal Fire said. The agency also reported that Highway 166 was closed between Highway 101 and New Cuyama.