From the Summary: "When civil unrest, violence, or natural disasters erupt in countries around the world, concerns arise over the ability of foreign nationals present in the United States who are from those countries to safely return. Provisions in the Immigration and Nationality Act (INA) provide for temporary protected status (TPS) and other forms of relief from removal under specified circumstances. The Secretary of Homeland Security has the discretion to designate a country for TPS for periods of 6 to 18 months and can extend these periods if the country continues to meet the conditions for designation. Congress has also provided TPS legislatively. A foreign national from a designated country who is granted TPS receives a registration document and employment authorization for the duration of the TPS designation."
CRS Report for Congress, RS20844
Congressional Research Service: https://crsreports.congress.gov/