Kohl's Corp.'s Web site crashed because of a surge in online traffic on Black Friday, a day when retailers offer bargains and the traditional start of the holiday shopping season.

Shoppers going to kohls.com were periodically greeted with a static screen and a message instructing them to come back later because the site "is not available at the moment."

Kohl's online traffic was "significantly higher" today compared with Black Friday last year, Julie Gardner, chief marketing officer of the Menomonee Falls, Wisconsin-based retailer, said in an e-mail.

"Kohls.com has been unavailable for intervals throughout the day," Gardner said. "We are working to resolve the situation as quickly as possible."

Top U.S. retailers saw a 27 percent rise in traffic as consumers took advantage of promotions online, according to ShopLocal, Gannett Co.'s online marketing service.

Kohl's, the fourth-largest U.S. department-store chain, allowed customers to create shopping lists online for the first time this holiday season. Starting Nov. 22, site visitors could print pictures and prices of items available today, Black Friday, the day after the U.S. Thanksgiving, Kohl's said.

"More than ever, consumers are using the Internet to save themselves time and money by pre-planning their visits to local stores," Vikram Sharma, chief executive officer of ShopLocal, said in a statement.

The number of online discounts jumped by 13 percent over last year and consumers' page views per visit increased by 12 percent, ShopLocal reported in the news release.

Kohl's fell $1.09, or 2 percent, to $54.45 at 3:41 p.m. in New York Stock Exchange composite trading. The shares have gained 50 percent this year.