For the second time in three weeks, Duke's campus was put on alert for a tornado warning.

At 6:13 p.m. Thursday, a DukeAlert was issued for a tornado warning that was in effect for Durham County. The campus sirens were activated, and members of the community were encouraged to seek shelter immediately. An all-clear was called at 6:33 p.m.

Vice President for Administration Kyle Cavanaugh said the University's severe weather group had been put on alert earlier in the day and was monitoring the situation prior to the National Weather Service's warning for the county. Rather than progressing from a tornado watch to a tornado warning, the call went straight to a warning, Cavanaugh noted.

"The communication system worked very, very well," Cavanaugh said. "It was up literally in minutes, before anything was really at risk."

Cavanaugh added that the current construction on campus requires particular attention during severe weather situations such as this.

Severe weather was observed across the state Thursday, with 74 of North Carolina's 100 counties under some sort of alert. Even after the tornado warning expired, thunderstorms were projected to continue throughout the evening in Durham.

The tornado warning comes after a similar situation Apr. 30, which also saw the campus sirens activated and a DukeAlert issued.