Chaos hit Delta Air Lines early on Monday morning as a loss of power at its Atlanta data center resulted in the airline grounding all its flights worldwide for several hours. Although the company's planes are now taking to the air, Delta informed customers flying today to expect delays and cancellations.

The problem completely crippled the airline, knocking out flight operations and bookings. Although it is yet to be confirmed by Delta, a member of the FlyerTalk forums was told by the captain of their flight that the cause was a fire in the data center:

According to the flight captain of JFK-SLC this morning, a routine scheduled switch to the backup generator this morning at 2:30am caused a fire that destroyed both the backup and the primary. Firefighters took a while to extinguish the fire. Power is now back up and 400 out of the 500 servers rebooted, still waiting for the last 100 to have the whole system fully functional

This is the second severe IT-induced travel disruption in recent weeks. On July 20, Southwest Airlines lost a router in its Dallas data center, which resulted in 2,300 flight cancellations. Southwest's CEO Gary Kelly described that event as a "once-in-thousand-year flood."

Meanwhile, Delta has issued a waiver for customers flying today (August 8) allowing them to change tickets without incurring any penalty fees.