French Expression of the Day: Coup de tonnerre

Why do I need to know coup de tonnerre?

You might have seen this expression used to describe the weather, but did you know it can also be a way to describe surprises?

What does it mean?

Un coup de tonnerre translates as a clap of thunder and the phrase can be used literally to describe the extreme weather phenomenon, for example Il y avait un coup de tonnerre et ensuite une forte pluie. (There was a crack of thunder and then heavy rain.)

But it is also used to describe something that takes you by surprise because it happens unexpectedly.

The expression un coup de tonnerre dans un ciel serein (a clap of thunder in a calm sky) or un coup de tonnerre dans un ciel bleu (a clap of thunder in a blue sky) translates as ‘a lightening bolt from the blue.’ 

This refers to rare instances when even though the sky appears to be clear, thunder and lightning can unexpectedly be seen and heard from far away.

Un coup de tonnerre can also be translated as ‘out of the blue’ or a ‘bombshell.’

You might see this expression used with different verbs. It can be paired with

être (to be) for example, c’était un coup de tonnerre (it was a bolt from the blue).

It can also be used with tomber (to fall) as in Le diagnostic est tombé comme un coup de tonnerre. (the diagnosis came like a bolt from the blue). 

Or, you can use the expression on its own without a verb, as in the headline below which says ‘France v Fiji live: Out of the blue, France loses to Fiji!’

 

How do I use coup de tonnerre?

Mais voilà que, coup de tonnerre dans un ciel bleu, j'ai appris l'existence de cette proposition-ci au moment où elle a été publiée.

But this simply came right out of the blue and the first time I read about it was when it was published in the book.

Cette affaire surgit comme un coup de tonnerre dans un ciel serein.

These events have come like a thunderbolt out of a clear sky.

(The above examples are from linguee.com)