Hundreds of people searched a sun-scorched area of Southern California on Tuesday for an autistic 11-year-old boy who was last seen at his home during the weekend.

Temperatures have topped 100 degrees every day since Terry Dewayne Smith Jr. went missing, but that didn't stop hundreds of emergency workers and volunteers from combing the dry brown hills of Menifee on Tuesday.

The Riverside County Sheriff's Department searched the region about 70 miles southeast of Los Angeles with the help of bloodhounds, helicopters and personnel on horseback.

There was concern because Terry may not be carrying any food, water or his medication.

"We have high hopes that he's still alive," Deputy Albert Martinez of the Riverside County Sheriff’s Department told The Press-Enterprise. "If you have water and shade, you can survive these elements."

Martinez said it is unclear how the boy went missing and indicated that there is no motive, the paper reported.

The 4-foot-8 boy with sandy brown hair and brown eyes was last seen Saturday night, wearing blue basketball shorts. Social media has been credited for the number of volunteers who’ve been showing up to look for the boy.

Molly Jenks brought her horse, Yeager, to assist in the search.

"Any little bit can help, and when I can do it on horseback, that's nice, too," she said.

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The Associated Press contributed to this report