Part of the roof was torn off the 9-10 building of the Washington Township High School around 11:40 a.m. Monday.
Some 2,800 students were dismissed early by order of the fire marshal.
All night-time activities scheduled for the 9-10 building have been canceled for Monday evening.
Police tell Action News that heavy wind may have caused some shingles to come loose.
"There were chunks of roof flying past the window," said student Miranda Hackett. "It was, like, really crazy to see part of the roof go flying by."
"The most important consideration, always, is the safety and well-being of our students," said Principal Joe Bollendorf. "To keep our kids safe, the decision was made to dismiss."
Water poured into the building through the roof. There are no reports of injuries.
While students were thrilled to get out early, it cause a disruption for some parents.
"I work for a builder, and I got to go back to work and work on my leaks right now," said parent Mike Romano as he picked up his child from school.
