A group of current and former Federal Emergency Management Agency (FEMA) officials warned Congress on Monday that the Trump administration's sweeping changes to the disaster relief agency could reverse decades of reforms made after Hurricane Katrina. The open letter was released as the U.S. this week marks 20 years since Katrina's 2005 landfall — sparking one of the worst natural disasters in U.S. history. The letter argues the Trump administration had made decisions that "hinder the swift execu