"The principles of disaster management assume a leadership role by the local and state governments with the federal government providing coordinated supplemental resources and assistance. A declaration of a major disaster or emergency must, in almost all cases, be requested by the governor, who at that point has declared that the situation is beyond the capacity of the state to respond. The governor also determines which parts of the state they will request assistance for and suggests the types of assistance programs that may be needed. The President considers the governor's request, in consultation with officials of the Federal Emergency Management Agency (FEMA), within the Department of Homeland Security (DHS), and makes the initial decisions on the areas to be included as well as the programs that are implemented. […] In addition to that assistance, other disaster aid is made available through programs of the Small Business Administration (which provides disaster loans to both businesses and homeowners), the U.S. Department of Agriculture (USDA), the Federal Highway Administration (FHWA) within the Department of Transportation (DOT) and the Department of Housing and Urban Development (HUD) (in the form of Community Development Block Grant funds being made available for unmet disaster needs). While the disaster response and recovery process is fundamentally a relationship between the federal government and the requesting state government, there are roles for congressional offices to play in providing information to the federal/state response and recovery teams in their respective states and districts. Congressional offices also serve as a valuable source of accurate and timely information to their constituents."
CRS Report for Congress, R41981