This September 2018 report is a thorough analysis of the FEMA response to four sequential disasters in 2017 - hurricanes Harvey, Irma, Maria, and the California wildfires-created an unprecedented demand for federal disaster response and recovery resources. According to FEMA, 2017 included three of the top five costliest hurricanes on record. The National Oceanic and Atmospheric Administration estimated that the cumulative damages from weather and climate related disasters in the United States were over $300 billion in 2017 alone. As of June 2018, Congress had appropriated over $120 billion in supplemental funding for response and recovery related to the 2017 hurricanes and wildfires. Further, in October 2017, close to 14,000 federal employees were deployed in response to the disasters. Given the scale and cost of these disasters, Congress and others have raised questions about the federal response and various recovery challenges that have arisen since the disasters. This report provides GAO's observations on: (1) federal and state preparedness and response coordination for hurricanes Harvey and Irma in Texas and Florida, and the California wildfires; (2) federal preparedness for and response to hurricanes Irma and Maria in Puerto Rico and the U.S. Virgin Islands; and (3) existing and emerging disaster recovery challenges highlighted by these disasters. GAO found that FEMA faced a number of challenges that slowed and complicated its response efforts to Hurricane Maria, particularly in Puerto Rico. Many of these challenges were also highlighted in FEMA's own 2017 hurricane after action report, including: the sequential and overlapping timing of the three hurricanes-with Maria being the last of the three-caused staffing shortages and required FEMA to shift staff to the territories that were already deployed to other disasters; logistical challenges complicated efforts to deploy federal resources and personnel quickly given the remote distance of both territories; and limited preparedness by the U.S. Virgin Islands and Puerto Rico for a Category 5 hurricane and incapacitation of local response functions due to widespread devastation and loss of power and communications led FEMA to assume response functions that territories would usually perform themselves.