"Flash floods" refers to a sudden and intense deluge of water that occurs very quickly, causing rapid flooding in a short period of time. Full definition
Is there a history of flash flooding in your area? (inc.com)
A tenant flood policy is the one and only way to protect against the risk of flash floods. (effectivecoverage.com)
This amount of rainfall was almost four times the monthly average and the majority fell within a two - hour period, causing flash flooding which killed eight people in total. (holiday-weather.com)