How much rain causes flooding?

HOUSTON, Texas (KTRK) -- Heavy rainfall is headed our way. Here are the numbers behind how much rain needs to fall for flood waters to rise.

• 2 inches in an hour floods streets


• Fast downpours of 4-6 inches in an hour and bayous and creeks are likely to flood


• 13 inches spread out over 24 hours will also flood bayous and creeks