Taking shelter is key if there’s a threat of global annihilation. Inform yourself where you can seek protection in your home, at work or other places you stay for a longer amount of time.
To survive storms or a nuclear attack it’s in general safer to select a room in the underground. If there’s a flood it’s of course the opposite. The shelter should be away from corners, windows, doors and the outside walls.
The length of staying inside your safe location can vary with every event. Be prepared to stay inside your shelter for at least a week. It can be only a short amount of time in case of a natural disaster for example, or longer during a pandemic.
Listen to your local authorities via radio and maintain a safety watch.