43 C.F.R. § 1815.0-5
Major disaster means any hurricane, tornado, storm, flood, high water, winddriven water, tidal wave, earthquake, drought, fire, or other catastrophe in any part of the United States, which, in the determination of the President, is or threatens to be of sufficient severity and magnitude to warrant disaster assistance by the Federal Government to supplement the efforts and available resources of States, local governments, and relief organizations in alleviating the damage, loss, hardship, or suffering caused thereby, and with respect to which the Governor of any State in which such catastrophe occurs or threatens to occur certifies the need for Federal disaster assistance and gives assurance of the expenditure of a reasonable amount of the funds of such State, its local governments, or other agencies for alleviating the damage, loss, hardship or suffering resulting from such catastrophe.
43 C.F.R. § 1815.0-5