Hordes of shoppers are descending on stores to snap up the best deals of the year.

Black Friday, the day when retailers traditionally turn a profit for the year, actually got a jump start this year as many stores opened just as families were finishing up Thanksgiving dinner.

Stores are experimenting with ways to compete with online rivals like Amazon.com that can offer holiday shopping deals at any time and on any day. And this year, crowds gathered across the country as stores such as Target and Toys R Us opened on Thanksgiving evening, while retailers from Macy's to Best Buy opened their doors at midnight on Black Friday.

"I only shop for sales," says Joan Riedewald, one of thousands of shoppers on line at Macy's flagship store in New York City's Herald Square.

Retailers are hoping that the earlier openings will help boost sales this holiday season. It is unclear how many shoppers took advantage of the earlier openings. But about 17 percent of shoppers said earlier this month that they planned to shop at stores that opened on Thanksgiving, according to an International Council of Shopping Centers-Goldman Sachs survey. Overall, it's estimated that sales on Black Friday will be up 3.8 percent to $11.4 billion this year.

Here, in images, are scenes from Black Friday from across the nation: