"We recognize that our customers depend on us now more than ever to provide the best holiday mailing season ever," said U.S. Postal Service vice president Nicholas Barranca.
Barranca spoke from the Postal Service's national command center, where radar and satellite images glow on video displays, alerting managers to problem weather, and where computer monitors laced with colored lights track the movement of cargo planes.
This center - and 11 other regional command centers around the country - will operate 24 hours a day, seven days a week, Barranca said.
Managers can shift planes and trucks to meet extra needs, reroute around bad weather and cope with problems at individual airports nationwide.
This year, the crush may be exaggerated by Y2K-wary people sending bill payments via paper mail rather than electronically, he said.
After Christmas, the command center will operate until Jan. 4 to handle any problems associated with the arrival of the year 2000, Barranca said.
"We have contingency plans available to move the mail," he said.
Officials urged people to help the mail move smoothly by using complete addresses, including ZIP codes, apartment numbers and a return address. ZIP codes are available by calling the post office or by checking the agency's Internet Zip Locator.
But Barranca urged people not to guess at a ZIP code, saying it's better not to use a ZIP code than to use a wrong one.