Thought this would be of interest. We (in the UK) seem to be getting more of these extreme rainfall events particularly over the last 3 summers.
http://www.walesonline.co.uk/news/wales-news/2009/06/10/freak-storm-brings-newtown-to-a-standstill-91466-23838885/
http://www.walesonline.co.uk/news/wales-news/2009/06/10/freak-storm-brings-newtown-to-a-standstill-91466-23838885/