The airport hoped to resume flights by 11:30 a.m. Wednesday, but the weather did not clear enough.
As of mid-day, 738 flights - half of the airport's average daily number - had been canceled.
The FAA originally held only incoming flights because of intermittent power outages.
Heath Montgomery with DIA said outages impacted the fuel farm on the north side of the airport. The fuel farm pumps fuel to the airport so that planes can refuel. Power has been restored, and the FAA planned to resume normal operations once the flights at DIA could refuel, take off and make room for incoming planes.
The outage also affected the Glycol (deicing) facility. This facility pumps the deicing fluid to trucks so they can apply it to the aircraft.
A brief power outage early in the morning took out the train service. That lasted only minutes.
Xcel was on hand throughout the morning to handle the intermittent outages.
Up to 12 inches of snow could fall at the airport with wind gusts of up to 46 mph.