In simple terms, a "rain storm" refers to a strong and heavy downpour of rain. It is when there is a lot of rain falling from the sky at once, often accompanied by strong winds and thunder.
Sentences with «rain storm»
She is not afraid of anything and loves to play in rain storms. (dailypuppy.com)
During rain storms she gets very nervous and takes meds to keep her calm. (puppyfinder.com)
We know that these kinds of rain storms and flooding will become more frequent and severe with global warming. (treehugger.com)