An older woman couldn't breathe, trapped in her Clarendon County house.
Hurricane Matthew in 2016 had knocked out her power and the power for a half-million others. She'd run out of oxygen and couldn't turn on the machine to keep supplying it. The lines were down, fallen trees sprawled across flooded roads. She had one thing going for her: a neighbor who was an amateur radio operator.
"He got on the radio and probably saved her life," said George Mudd of the South Carolina Healthcare Amateur Radio Team.
South Carolina communication managers call Hurricane Hugo in 1989 the defining moment. In the wreckage the next morning, if you asked a local town police officer if it was safe to drive somewhere, you'd get a shrug. No agency could talk to any other agency. Nobody knew.
Today, if a disaster strikes in South Carolina and all other communication is disrupted, the SCHEART cadre of 1,500 to 2,000 amateur radio operators is a last line of defense — important enough that a representative has a seat in the Emergency Operations Center in Columbia.
If the radios go dead, the operators are still able to communicate through a network of walkie talkies.
"We're the backup emergency communications when everything else fails. We report trees down, flooding, anything we can see that the authorities need to know about," said Mudd, operator KK4F.
And yes, everything else can fail, even in the high-tech age of cellular and satellite communications.
"There are some vulnerabilities. The system could go down or just be overburdened. Some of the managers might be more dependent on infrastructure (communications) than they should be," Mudd said.
The ham radios are part of a larger disaster-response communications plan set up since Hugo.
The state has assembled Palmetto 800, a trunked statewide network designed to let multiple agencies communicate. More than 700 agencies and 70,000 users are now part of the network. It's been expanded to agencies in the border areas of both North Carolina and Georgia.
"A network user mobilized to assist in a disaster is not tied to towers in their 'home' district," said Kelly Coakley, the strategic communications director for the S.C. Department of Administration.
During Hurricane Florence in 2018, the Palmetto network was the communications platform used to direct coastal evacuations beforehand, then rescue and recovery efforts afterward, she said.
There's also what's called a tactical redundant network for public safety officers, 120 conventional radio "repeaters" that receive and transmit signals, essentially bouncing radio calls where needed. Each county in the state has at least one, with others dispersed among high-communications traffic sites.
On the national level, the Cybersecurity and Infrastructure Security Agency — the agency whose primary job is to combat cyberthreats — assesses communications every five years, according to a Federal Emergency Management Agency spokeswoman.
During a disaster, the agency provides a federal link for state and local groups.
And if all else fails, there's SCHEART — formed originally so hospitals could communicate during disasters — and people like Mudd.
"I can take a 5-watt walkie talkie here in Sumter and talk to someone in Georgetown or Charleston," he said.