DENVER — Santa already is piling up big numbers on social networking sites this season, so the volunteer Santa-trackers at NORAD are bracing for tens of thousands of calls and emails when their operations center goes live on Christmas Eve.

“We expect our numbers to be very high this year,” said Joyce Creech, project leader for NORAD Tracks Santa at Peterson Air Force Base in Colorado Springs, Colo.

Last year, NORAD Tracks Santa volunteers answered 80,000 phone calls on Christmas Eve, Creech said. They also answered 7,000 emails.

The North American Aerospace Defense Command has been telling anxious children about Santa’s whereabouts every year since 1955. That was the year a Colorado Springs newspaper ad invited kids to call Santa on a hotline, but the number had a typo, and dozens of kids wound up talking to the Continental Aerospace Defense Command, NORAD’s predecessor.

The officers on duty played along and began sharing reports on Santa’s progress. It’s now a deep-rooted tradition at NORAD, a joint U.S.-Canada command that monitors the North American skies and seas from a control center at Peterson.

NORAD’s Santa updates are just about everywhere — on Facebook, Twitter, YouTube, www.noradsanta.org and television. And this year, there’s a new Santa-tracking app for smart phones, built by visionbox, a Colorado Springs software developer.

It has the Elf Toss, a game similar to Angry Birds.

The app was downloaded more than 234,000 times from Android Market and iTunes App Store by mid-December, Creech said.

NORAD Tracks Santa already has had more than 754,000 “likes” on Facebook this year, compared with 716,000 through Christmas Eve last year. Twitter numbers also are up, with 60,000 followers so far this year, up from 54,000 last season.