how do they form
a flood is from days of heavy rain and/or melting snow. and it also can happen when water goes over river, sea banks.
april-may 1927 killed 500 people and left 600,000 homeless. the other one is from august 16 2004 killed 0 people but caused extensive damage.
how to prepare
to prepare you can put sandbags up and get a phone that warns you that a storm is coming.