Simplify the following text for a Grade 5 native English-speaking person.
Original: The city of Toowoomba , in the Darling Downs , was hit by flash flooding after more than 160 m of rain fell in 36 hours to 10 January 2011 ; this event caused four deaths in a matter of hours .
Simplified: The city of Toowoomba , in the Darling Downs , was hit by flash flooding after more than 160 m of rain fell in 36 hours to 10 January 2011 . This event caused four deaths in a matter of hours .