The Federal Emergency Management Agency is seeking to show its mettle after the debacle of the post-Maria response in Puerto Rico. Although President Trump has celebrated the effort as a success, the agency itself acknowledged that it had inadequate supplies and had underestimated what it would need.

In the spotlight is Brock Long, Mr. Trump’s FEMA chief, who received accolades for the agency’s response during Hurricanes Harvey and Irma but has been under scrutiny for his use of government vehicles. In April, Mr. Long announced that North Carolina would be the first state where FEMA staff would embed with a state emergency management agency.

Gov. Roy Cooper of North Carolina, a Democrat, must also prove himself after criticism that his administration spent only a fraction of disaster funding that Congress allocated to the state for rebuilding after Hurricane Matthew. (Mr. Cooper’s office notes that the state has spent a total of $751 million of state, local and federal money on Matthew recovery, and the governor and legislative leaders are planning for a special session focused on Florence relief.)

Gov. Henry McMaster of South Carolina, a Republican, also has something to prove — that he can step out from the shadow of former Gov. Nikki Haley. Mr. McMaster, the former lieutenant governor, ascended to his state’s top job last year when Ms. Haley joined the Trump administration. He now faces the most substantive test of his tenure, weeks before voters will decide whether he has earned a full term in Columbia.

More than a week after the storm made landfall as a Category 1 hurricane, the scope of the devastation is still becoming apparent. In North Carolina, dozens of wastewater treatment plants were shut down, inundated or otherwise compromised, according to FEMA. Four lagoons that receive hog waste failed, with nine others inundated and four overtopped.

Another potential biohazard involved poultry. Andrea Ashby, a spokeswoman for the North Carolina Department of Agriculture, said that the storm and flooding caused the death of 3.4 million chickens or turkeys. A FEMA report Thursday said that millions of “impacted” chickens were to be found in rural Lenoir County alone. But in a sign of the fog-of-war nature of the crisis, two officials in Lenoir County — Bryan Hanks, the county spokesman, and Tammy Kelly, the cooperative extension director — said they had heard no reports of widespread poultry deaths there.