NATCHEZ — Entergy Mississippi is investigating what caused power outages for approximately 5,200 power customers Thursday.

The first outage lasted from 12:30 a.m. to 1:03 a.m. Thursday, when Entergy lost power at several substations. A second followed from 9:02 to 9:08 a.m.

Entergy Mississippi Spokesman Tim Runnels said the outages were caused by trips in the transmission line across the Mississippi River.

“When we lose those transmission lines, we lose entire substations, and so when it tripped we lost power to 5,196 customers,” Runnels said.

“They are investigating now what caused those trips to occur. The good news was that it was a short duration, but it still impacts customers, and we don’t want to do that.”

Both Natchez hospitals, the industrial park near the port and numerous residences  — a total of 5,196 customers — on the Mississippi side of the river were affected. Many of the traffic lights in Natchez were out of commission during the outages.

Runnels said Entergy worked to communicate the situations with the city and the hospitals as they developed.

The issue also affected power on the Louisiana side of the river.

In a statement from the City of Vidalia, utility officials said that even though the city does not get its power from Entergy, it shares the transmission line and the outages were felt citywide and in some areas outside the city.

Vidalia purchases its power from the Louisiana Electric Power Association.