Authorities in California are searching for a 69-year-old woman who went missing while hiking in the Mojave Desert.

Arizona resident Barbara Thomas does not have the means to survive the sweltering heat expected this week, the San Bernardino County Sheriff’s Office said.

Thomas was last seen Friday wearing a black bikini, a red baseball cap and tan hiking boots with black socks. She got separated from her husband while they hiked about 20 miles north of the Interstate 40 freeway.

Temperatures in the Mojave Desert exceeded 100 degrees over the weekend and are expected to remain in triple digits this week. Thomas does not have a cellphone or any supplies, authorities said.

The sheriff's office said there have been no sightings of Thomas, who is 5-foot-9 and 130 pounds. Anyone with information on her whereabouts is urged to contact authorities.

Found alive: Woman missing in remote area near California-Nevada border, family fears she was abducted

Another woman who went missing in California's wilderness on Friday was found alive on Monday. Authorities searched for Sheryl Powell, 60, who was camping in the White Mountains near the Nevada border.

Her daughter shared the news in a Facebook post. A photo shows Powell smiling in a hospital bed with her family surrounding her.

This article originally appeared on USA TODAY: Arizona woman Barbara Thomas missing in California's Mojave Desert