A Watertown school will reopen Wednesday after some exploding tiles forced classes to be canceled Tuesday. Tiles in the cafeteria started to buckle and explode Monday at St. Henry’s Catholic School. “And I looked at the tiles on the floor. (They) were raising up and flying across the kitchen floor. So, we got out of the cafeteria and told the kids to go up to their classrooms. Eventually, they were evacuated,” St. Henry’s Cooking Manager Diane Dannenberg said. “It looked like the movie ‘Tremors’ where something was tunneling underneath the floor.” Some described exploding, but the floor definitely buckled. The city’s building inspector said the part of the building affected was built in 1952. Investigators are looking at all sorts of possibilities to explain why these tiles lifted off the ground. After 20 years as the city’s building inspector, Joe Heimsch said he was baffled after first looking at this basement.