Nearly 20 people were desperately scouring the Mojave Desert in California on Wednesday for any sign of a 69-year-old bikini-clad Arizona woman who reportedly vanished Friday while hiking with her husband, and who still may be stranded while sweltering, triple-digit temperatures baked the region.

Barbara Thomas, of Bullhead City, Ariz., was last seen Friday hiking with her husband, Robert, in the desert about 20 miles north of Interstate 40, east of Kelbaker Road, according to the San Bernardino County Sheriff’s Department.

On Tuesday, the agency said 20 Search and Rescue volunteers, and deputies assigned to the River Station, continued combing through the unforgiving wasteland in search of the 69-year-old.

"Off-road vehicles are being utilized to allow searchers to cover additional area," the sheriff's office said.

BIKINI-CLAD WOMAN, 69, REPORTED MISSING AFTER HIKING IN MOJAVE DESERT IN CALIFORNIA AMID HEATWAVE

Thomas was last seen wearing a black bikini, red baseball cap and tan hiking boots with black socks. She is described as 5 feet 9 inches tall, weighing 130 pounds and with blonde hair and green eyes.

"There have been no sightings of her at this time," the latest update Wednesday from authorities read. Search efforts resumed at sun up on Wednesday and focused on the area of Kelbaker/Hidden Hills near Interstate 40.

The 69-year-old reportedly did not have any supplies or her cell phone at the time she was reported missing. Authorities have not released additional information about how the couple became separated.

CALIFORNIA HIKER MISSING FOR 4 DAYS IS FOUND ALIVE, DAUGHTER AND INVESTIGATORS REVEAL

Search and rescue members, including sheriff's deputies, K9's, park rangers, and a helicopter have been deployed in the Mojave Desert as part of the team looking for Thomas.

Temperatures have topped 100 degrees in the days since she was reported missing, and is expected to continue hitting triple digits the rest of the week.

CLICK HERE FOR THE FOX NEWS APP

The National Weather Service warns heat is the top weather-related killer in the U.S. Besides limited time outdoors and dressing appropriately, people can practice heat safety by staying hydrated, limiting strenuous activities and finding shade

Anyone with information regarding Barbara's whereabouts is urged to contact the Colorado River Station at 760-326-9200 or Sheriff's Dispatch at 760-956-5001.