Former Chicago Man And His Girlfriend Disappear In California

(CBS) -- Teri Talan clings to her iPad, watching for any updates on where her son – 33-year-old Aaron Morganstein -- and his girlfriend, 27-year-old Mariya Mitkova could be.

"I vacillate from being hysterical and crying," Talan says.

The two were last heard from Saturday evening.

The couple traveled from outside Los Angeles and may have been heading to the Imperial Sand Dunes.

"They'd do that several times a year, so, this was not unusual," Talan says. "What's unusual is that Aaron would miss work."

On Monday, Morganstein, a professional photographer previously from Chicago's Rogers Park neighborhood, missed a photo shoot in San Diego the same day friends filed a police report.

Friends began searching, most recently from the air.

The biggest problem is trying to determine where to look. The dunes sprawl more than 600,000 acres and Joshua Tree National Park -- a place where the couple could have stopped on the way --- spans nearly 800,000 acres.

Police say the two were driving a 2002 dark blue Subaru Outback.

Morganstein's mother is on the way to California to help in the search.