LAS VEGAS — Revelers packed as tightly as the Las Vegas Strip would allow brought in 2011 with booming shouts and cheering in the street to keep up with an eight-minute fireworks show from the roofs of seven casinos.

The pyrotechnics combined with glittering flash bulbs and bright neon to light up the cold night sky as a joyous, bundled-up crowd welcomed the first moments of the new year early Saturday.

Jay-Z and Coldplay counted down the year’s final moments for a black-tie ballroom crowd filled with celebrities and thousands watching on the marquee of the $3.9 billion Cosmopolitan of Las Vegas.

Downtown, Mayor Oscar Goodman led a countdown underneath the giant video canopy of the Fremont Street Experience, touching off a combined display of live and video fireworks.

Tourism officials expected 320,000 to celebrate the new year in Sin City, a welcome sign for a town dependent on gambling and visitation — though tourists are expected to spend less than last year.

"My resolution will be to make the new year better than this year," said DaLynn Alley, 27, of Tahlequah, Okla. "It wasn’t bad, but next year will be better — I just know that."

Alley was in Sin City for one night with her best friend before traveling to Glendale, Ariz., for Saturday’s Fiesta Bowl.

"We’re here to sow our royal oats and write the new chapter in our book," said her friend, 31-year-old Joel Deerinwater.

The Cosmopolitan show was the top ticket for a weekend celebration for the resort that opened two weeks ago. Casino executives and celebrities including Jamie Lynn Sigler, Giada De Laurentiis, Alex Rodriguez, Cameron Diaz and a bevy of others dined before the show on veal, truffle-baked Maine lobster and foie gras at a private dinner for 1,400 with a performance from Ben Folds.

Those not lucky enough to be inside dealt with below-freezing temperatures even hours before midnight came.

The National Weather Service said the overnight low was expected to be 23 degrees.

"We obviously are not going to warm up," meteorologist Larry Jensen said.

Las Vegas police said at 3 a.m. Saturday that there were 24 misdemeanor arrests and eight arrests for driving under the influence. Police said 34 traffic accidents were reported in nearly seven hours.

Casino-hotels in northern Nevada also expected to be without vacancies, given fresh snow at Lake Tahoe.