Union dockworkers at ports across the U.S. began walking picket lines early Tuesday, snarling the movement of billions of dollars' worth of goods.

A strengthening retail market and new customers are combining to drive growth at the Port of Savannah. The port handled 490,330 twenty-foot equivalent container units (TEUs) last month, up 22% compared to May of last year, the Georgia Ports Authority reported Thursday.

The global supply chain backup is clogging the Port of Houston, but it's not as bad as the huge bottleneck at the Port of Los Angeles.