(CNN) -- Instead of presents, there might be IOUs under some Christmas trees in Colorado on Sunday.
This week's snow storm has delayed the delivery of some 50,000 UPS packages into the Denver area, CNN affiliate KUSA reported, citing a company spokeswoman.
"We know it's Christmas. We apologize for the delay, but we can't control the weather," Natalie Godwin said. "As soon as we can, we're going to get all of those packages delivered."
Hundreds of people waited in line Saturday outside of the UPS building in Commerce City, hoping to pick up their packages, KUSA said.
A winter weather system blasted broad swaths of the West and Midwest this week, dumping heavy snow.
"This makes no sense. They get paid. It snows in Colorado. That's what it does here. So how are you in the business that you can't deliver what you say?" Jacqueline Camack, a frustrated customer, told KUSA.
UPS has said it planned to make more than 120 million deliveries this week, its busiest of the year.