SALT LAKE CITY — Your greeting cards may have all been sent, but the Christmas rush is just beginning for United States Postal Service employees.

The week before the holidays, historically the busiest for those whose job is to sort and deliver packages and cards, is set to be the busiest yet for Utah postal workers.

Local USPS facilities are expected to handle 550,000 packages on Monday — about 90,000 more packages than on the busiest day of 2018.

The package boom is likely due to a combination of local growth and an increase in people shopping online, said Salt Lake district manager Laura Hubrich. That includes packages coming into Utah for local shoppers and those being sent out of state by Utah-based businesses.

“The economy is growing in Utah, which is great,” Hubrich said.

Of course, more packages means more to do for those working this holiday season.

An estimated 400 people will work in the Salt Lake facilities on Monday handling those 550,000 packages, Hubrich said. Some will be temporary employees — the district has hired about 200 seasonal workers this year. Others will be regular employees working additional hours.

To keep holiday time morale high, the facilities hold special events for employees through the week, such as a “funny hat day,” Hubrich said.

“We try to make it as festive as possible because we know people are putting in so many hours,” she said.

While Monday is expected to be the busiest day, especially for outgoing packages, the following Wednesday, Thursday and Friday — when packages sent from elsewhere Monday will arrive in Salt Lake City — will also likely be busy.

For those shipping packages to other states, excluding Alaska and Hawaii, the recommended send-by date to ensure they arrive in time for Christmas are Dec. 20 for first-class mail, Dec. 21 for priority mail, and Saturday for packages sent through retail ground service.

Utahns sending packages to other Utahns will likely want to put them in the mail by the Saturday before Christmas, Hubrich said.

Postal employees will get some peace from the chaos on Christmas Day, a postal holiday. But then it’s back to work, dealing with the next round of packages: returns.

“We can help with that, too,” Hubrich said with a laugh.