roof collapse

I read an article about a school in orange county that had a roof collapse while a class was in session. On monday morning during heavy rainfall, water built up on top of the orange county school and let to the collapse of the roof. There were four drains and all but one was not working properly and caused a water build up. The water built up so much , the roof gave away and the front of the room's ceiling collapsed. Everyone in the class started to run out of the room when the rest of the ceiling came down. While the chaos was happening desk were pushed together and a few people were trapped. Rescuers went inside the building 3 times and made sure everyone made it out ok. Everyone made it out alive but some suffered some injuries.