Au Cas Où + Conditional Mood
The phrase au cas où + conditional mood translates to “in case” in English. It introduces a clause that describes a possible or hypothetical situation. You can download a PDF of this lesson guide in my private French Grammar Library.
In French, “au cas où” is followed by a verb in the conditional mood, as it expresses an event that is uncertain or dependent on certain conditions.
It is tempting to use the subjunctive mood with au cas où, but that would be incorrect.
Why “au cas où” Is Followed by the Conditional Mood
The conditional is used with “au cas où” because it signals a hypothetical scenario or a precautionary measure. This usage reflects politeness, uncertainty, or a non-committal stance, which aligns with the purpose of “au cas où”, to prepare for a potential event that may or may not happen.
Structure
Main clause: States the action or precaution being taken.
Subordinate clause with “au cas où”: Describes the hypothetical situation in the conditional.
Examples
1. Basic Example
Apporte un parapluie au cas où il pleuvrait.
Bring an umbrella in case it rains.
→ il pleuvrait (it would rain) expresses a possible situation.
2. Politeness or Precaution
Je te laisse mon numéro au cas où tu aurais besoin d’aide.
I’m leaving you my number in case you need help.
→ tu aurais besoin (you would need) softens the suggestion of need.
3. Negative Hypothetical
Elle a tout vérifié au cas où quelque chose ne fonctionnerait pas.
She checked everything in case something wouldn’t work.
→ ne fonctionnerait pas (wouldn’t work) emphasizes the hypothetical failure.
4. Future Event with Hypothetical Preparation
Prenons une lampe de poche au cas où il y aurait une coupure de courant.
Let’s take a flashlight in case there’s a power outage.
→ il y aurait (there would be) describes the possible occurrence.
Why Not Use the Subjunctive or Indicative Mood?
The subjunctive is reserved for expressions of doubt, emotion, or necessity. It does not align with the hypothetical or precautionary tone of “au cas où”.
The indicative describes factual events and certainties. Since “au cas où” implies uncertainty, the indicative is not appropriate.
Common Contexts
1. Travel and Packing:
Prenez votre passeport au cas où vous en auriez besoin.
Take your passport in case you need it.
2. Safety Precautions:
Installe une alarme au cas où quelqu’un essaierait d’entrer.
Set up an alarm in case someone tries to break in.
3. Communication:
Laisse-moi un message au cas où je ne serais pas disponible.
Leave me a message in case I’m not available.
By consistently using au cas où + conditional mood, you signal the hypothetical and precautionary nature of the situation, maintaining clarity and proper grammar.
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