The phrase "massive flood" refers to a very big and severe overflowing of water that covers a large area, causing damage and affecting many people or things. Full definition
Why can't we ever just have two hours of massive flooding and streets being ripped open? (filmjunk.com)
To keep the big polar ice sheets largely intact and prevent massive flooding will require limiting warming to just 2 °C. (newscientist.com)
The roughly $ 1 billion left in FEMA's Emergency Response Fund was expected to run out as soon as the end of the week, just as Category 5 Irma could be pounding Florida and less than two weeks after Hurricane Harvey caused massive flooding in Houston. (chicagotribune.com)