(CNN)A fire sparked by a pyrotechnic device used during a gender reveal party has burned more than 10,000 acres since Saturday.
The El Dorado Fire in Southern California's San Bernardino County has scorched 10,574 acres and was 16% contained as of Tuesday, according to fire officials, who say it's "one of the most dangerous fires" they've seen in the area.
The fire was caused by a "smoke-generating pyrotechnic device" used at a party on Saturday morning in El Dorado Ranch Park in Yucaipa, about 70 miles east of Los Angeles, Cal Fire investigators determined.
Evacuations have been ordered in the area as homes have been threatened. About 87 large wildfires are burning across the United States, with California hit hardest.
"In my 30 years as a citizen in Yucaipa, I have never seen such a large fire," Yucaipa Mayor David Avila said during a Monday news conference. "As a retired firefighter with 32 years of experience, I can assure you I witnessed one of the most dangerous fires that we can have in this area."