Translation of "D'avertissement" in English

Il n'y a pas eu d'avertissement.

There was no warning.

Que cela serve d'avertissement à Dan.

Let this be a warning to Dan.

Nos symboles d'avertissement devront changer avec nous.

Our warning symbols will have to change along with us.

Leur couleur vive sur le dos sert d'avertissement.

And the warning is that bright color on their back.