FedEx Corp. warned customers of possible delivery delays on March 11 after record rainfall at Memphis International Airport affected the company's world hub.
The Memphis-based company also said it was addressing information technology difficulties that were compounded by weather problems.
Flightstats.com, an online flight tracking service, showed more than 100 FedEx flights out of Memphis delayed overnight.
FedEx spokesman Jim McCluskey said, "The widespread lingering weather system has delayed flights in our network, including Memphis. This has affected service, but we are working hard to move volume and meet service to the best of our ability. "
McCluskey said five weather-delayed flights missed overnight sorts at the two largest U.S. hubs, Memphis and Indianapolis.
Smaller cargo carriers serving Memphis, including Mountain Air Cargo, also experienced delays, Flightstats.com said.
Airport spokesman Glen Thomas said by e-mail, "Our airfield has been under normal operations and we have not experienced any significant issues due to the rain."
The National Weather Service recorded 4.53 inches of rainfall at the airport on March 9, a record for the date, and 3.43 inches on March 10, another record.
FedEx posted alerts about weather and IT issues on its website at fedex.com.
"FedEx Express experienced substantial flight delays at the Memphis hub due to continuing effects of a massive weather system that is causing extensive flooding. Potential delays are possible for package deliveries across the U.S. with a delivery commitment of March 11, 2016," one alert said.
Another said, "We apologize for the inconvenience our customers may encounter as we experience difficulties across several areas of our IT systems that are compounded by severe weather-related delays. We are working to resolve the issues as rapidly as possible and have implemented contingency measures to lessen any impact on http://fedex.com capabilities and deliveries."