David Zalubowski/AP Park ranger Kevin Sturmer, right, tells Sarah Schlesinger of Boulder, Colo., that Trail Ridge Road is blocked to vehicles after a light overnight snow in Rocky Mountain National Park Saturday, Dec. 22, 2018, in Estes Park, Colo.

Visitor centers at Rocky Mountain National Park were locked Saturday and roads were closed or unplowed because of the federal government shutdown.

But the U.S. military said the shutdown won’t affect NORAD Tracks Santa, its 63-year-tradition of answering phone calls from children on Christmas Eve asking where Santa Claus is at the moment. The operation is run by volunteers Peterson Air Force Base and is funded by the Department of Defense's budget that was approved earlier this year.

In 2017, the Santa Tracker drew 126,000 phone calls, 18 million website hits, 1.8 million followers on Facebook and 179,000 more on Twitter.

It takes 160 phones to handle the calls that pour in. New volunteers get a playbook that briefs them on the questions kids might ask. Big screens on the walls show a Santa icon making blistering progress around the globe. U.S. and Canadian officers do live TV interviews from the phone rooms.

"It really gets you into the Christmas spirit," said Hill, a student at Mississippi State University who got involved through Air Force family members stationed in Colorado Springs.

Rocky Mountain National Park’s gates were open, but staffing was cut back and roads were not being cleared of new snow.

Roads that were passable at the time of the shutdown would remain open unless conditions worsened, park spokeswoman Kyle Patterson said.

“This is really disappointing,” said Sarah Schlesinger of Boulder, who went to the park with two nieces from Florida who had never seen snow before.

“It’s time for a new administration,” she said.

Her nieces did get to go sledding, though.

Vasilis Vasileiou of Ioannina, Greece, was making his first trip to the U.S. West and was disappointed to find the visitors centers closed. But he said he has encountered similar situations at home.

“This is not too frustrating for me because where I come from in Greece, we deal with strikes and shutdowns on an everyday basis,” he said. “Nothing significant has happened here, though, because we can still walk around outdoors.”

But he wished the visitor center was open so he and his travel companion could ask about what to see.

Rocky Mountain National Park, just 65 miles from downtown Denver, is the fourth most popular national park in the country. RMNP drew 4.4 million visitors in 2017.

Colorado’s three other national parks — Mesa Verde, Great Sand Dunes and Black Canyon of the Gunnison — said on their Facebook pages that some areas remained accessible but that could change without notice and no ranger services were available. Dinosaur National Monument in northwestern Colorado had the same message on its Facebook page.

Bent’s Old Fort National Historic Site was closed to protect park resources and visitors, said Rick Wallner, the site’s chief of interpretation.