Lots of water suddenly falling at once is what causes a flash flood and this can last for ages which is why sometimes you can get really heavy flooding. The roads will fill with water as the drains can't take any more and you will have to run for cover!
Hope i helped ;)
there were 7 rescue helicopters scrambled in the boscastle flash flood according to the BBC
flash flood wall
How big can a flash flood be?
In 2007 in July Glouctestershire was hit by flash flood (a flash flood is a flood that happened really quick due to lots of rain)
flash flood
No there is no flash flood.
1 in August 17 1998 flash flood and 1 in March 2011 flash flood
That would be called a flash flood.
A flood timberland is a flash flood. A flash flood is the rapid flowing of low-lying areas such as rivers, basins, and dry lakes.
Flash flood - A flash flood is a sudden inundation of water in low-lying areas, usually brought on by heavy rain or a dam break
Flash flood comes and goes really quick. A flood takes longer and takes longer to go away.
A Flash Flood of Colour was created on 2012-01-16.