Desperate Southern Californians are flooding across the Mexico border in search of water, toilet paper and other items.

An hour before one of two Costco locations in Tijuana opened Tuesday morning, there was already a line forming. Employees said that in recent days, by 10 a.m., there have been 600 people in line. They know this because the store only has 600 shopping carts and those have all been taken.

They also said it’s been busier than during the holiday season as people from north of the border continue their quest for items they can’t find at stores in San Diego and elsewhere in Southern California.

“It is hard for us to come … here to get things, but still, we want to try,” said Maria Castro, who lives in Los Angeles.

She said the Costco store in Fullerton, where she actually works, can’t keep up with the demand for water, bread and toilet paper, among other things.

Castro drove more than two hours to get to the Calimax supermarket about a mile south of the border, where she found water, rice and beans.

Others, like San Diego resident Carmen Jimenez, left the same store with a trunk full of toilet paper, paper towels and more.

“They’re still not very bad right now here, so they have a lot of products,” Jimenez said. “But they’re not selling you over four packages of anything; four is the maximum.”

One downside to this, according to the manager at the Calimax store, is that they are having a tough time keeping the shelves stocked with merchandise due to the crush of people from Southern California.

Visit the BorderReport.com homepage for the latest exclusive stories and breaking news about issues along the United States-Mexico border.