Good questions to ask your school: What are the plans? How often do you practice them? If my child(ren) get moved from the school, where will they go & how long will they have adult supervision?
The idea is both for you to find out and to get those in charge thinking about helping the 100-1500 kids in an emergency.
( another good question -- does your school have a weather alert radio in the main office & is it plagged in?)