'Gender reveal party' sparked California wildfire

Officials in California are saying that a wildfire there may have been sparked by a "gender reveal" party for a new baby that went awry.

According to CalFire, a smoke-generating pyrotechnic device caused the El Dorado Fire in San Bernardino county.

The agency said it was one of three major fires burning through counties in Fresno, San Bernardino, and San Diego.

And added that they had increased staffing in preparation for "critical fire weather."

Late Sunday, California Governor Gavin Newsom declared a state of emergency in the affected counties.

More than 200 people were airlifted to safety out of Sierra National Forest, after one fast-moving wildfire cut off the only road out of a popular recreational site called the Mammoth Pool Reservoir.

The Madera County Sheriff said on Twitter that some twenty evacuees had been taken to area hospitals, as the Creek Fire grew rapidly.

Since starting on Friday, it's burnt some 45,000 acres, forcing evacuations and road closures in the Fresno area in central California.

Nearly 15,000 firefighters were battling 23 blazes across the state as of Sunday.

A dangerous heat wave has baked swathes of the western United States over the holiday weekend.

Many locations in California registered record-high temperatures on Saturday.

And the National Weather Service warned that "sweltering" heat would persist, creating ideal conditions for wildfires.

Eight people have been killed and some 3,300 structures have been destroyed in the past three weeks.