Offline emergency preparedness: a guide for households

Most emergency advice assumes the internet will be there when you need it. In a long power cut, a flooded exchange or a cyber-attack on a network provider, it will not be. Offline emergency preparedness is the work of arranging your household so that losing the network changes as little as possible: you still know where everyone is meant to be, you still have the information you need, and you still have a way to make yourself heard across a street.

It starts with a plan rather than with equipment. Two meeting points are enough for most families: one close to home, for a fire or a local incident, and one further out, for the case where the neighbourhood itself has to be left. Everyone should be able to recite both without looking them up, because the moment you need them is the moment your phone is flat. Write them down as well, on paper, and keep that paper somewhere you would actually reach for it.

Next comes the family record. Names, birthdays, blood types, medications, allergies, the phone number of a relative outside your area and any medical details that a stranger would need to help. Keep a copy offline on each adult's phone and a paper copy in a bag or a drawer. In an outage, a list you can read without a signal is worth more than an app that needs one.

Then practise the signalling. Light and sound travel further than people expect when there is nothing else competing with them: a torch flashed in a pattern, a siren, a whistle, a knock on a pipe. Agree in advance which signal means “I am safe” and which means “come to me”, then rehearse it once with the lights off, so that the first time you use it is not the first time you have tried it.

Finally, charge and store. Keep a power bank charged, keep a torch where you sleep, keep water and any medication in one place, and assume the first hour of an outage is the one where everyone is trying to call at once. A short message sent early often gets through when a call later will not.