How do you write a crisis message that actually gets read?

During an incident you have one message and a few minutes. The structure decides whether people do what is needed.

Put the action first

Not "we wish to inform you that an incident has occurred", but "do not come to the site today". What the recipient must do belongs in the first seven words.

One message per instruction

Two instructions in one SMS means half of them will remember one. Rather send twice.

Say who is sending

An urgent message from an unknown sender is distrusted. Use a recognisable sender name, and the same one as in earlier messages.

Promise a follow-up

"New message at 16:00" prevents a wave of calls to your reception. Then keep that promise, even if there is nothing new.

Preparation matters more than wording

Make sure the list is current, that more than one person can send, and that this person can do so from home. Most crisis communication fails not on the text but on a password nobody has to hand.