They are closing many of the schools in counties in the central part of the state to use the facilities for evacuation centers. They also need the school buses to help move people on the coast with no access to transportation. They are doing this because Governor McMaster issued mandatory evacuations for the entire coast of SC. They have approximately 1 million people in the low country to evacuate. He is being proactive like Nikki Haley was. I hope that clears up the reason.