SIOUX FALLS, SD (KELO) — It’s been nearly one-year since Amazon first announced it was going to build a massive fulfillment center in Sioux Falls. Now, construction crews at the site are heading into the winter right on schedule. Even city building officials are surprised at how quickly the fulfillment center is going up.

The Amazon fulfillment center is now fully enclosed. What was a five-story framework of beams back in the spring has been encased in concrete and steel siding as crews start to work on the interior.

“They’re finishing the walls, putting in the electrical and mechanical systems, all those types of things that you would do with any type of building. And then they’ll start putting equipment in pretty soon, as well,” Director of Planning & Development Services Jeff Eckhoff said.

Jeff Eckhoff says he’s surprised and impressed by the progress, considering the size and scope of the $280-million project.

“Because typically, a build on something this size could be almost two years and they’ve done it in about less than a year-and-a-half,” Eckhoff said.

Amazon can make quick work of the project because the company has had plenty of practice building fulfillment centers across the country.

“They know what they’re doing, so it does go up very fast. This isn’t their first rodeo,” Chief Building Services Official Butch Warrington said.

City inspectors are at the site just about every day. And even veterans with the city are taken aback by the open spaces inside.

“Oh, there’s always a wow factor for any building. But yes, there is, you go out there, it’s a big building,” Warrington said.

The warm weather has helped push construction along even as supply chain backlogs present challenges throughout the industry. The city expects construction of the Amazon center to be completed, on-schedule, in the spring.

The Amazon center expects to employ 1,000 full-time workers when it opens next year.

We reached out to Amazon Friday, but the company told us they’re not in a position to provide any update on construction, at this time.