gully-washer
Definitions
A heavy, sudden rainstorm that causes water to run in torrents.
A severe downpour capable of eroding gullies in the ground.
Examples
We had to pull the car over to the side of the road because the sudden gully-washer made it impossible to see through the windshield.
The dry creek bed filled up in minutes during the afternoon gully-washer.
Make sure you close the windows before that gully-washer hits, or the whole living room will be soaked.
Synonyms
downpour deluge cloudburst torrent rainstorm waterspout monsoon