A terrifying alert appeared on some cell phones along the East Coast and the Caribbean Tuesday morning, warning residents of an impending tsunami.
But the National Weather Service issued an all-clear within minutes, letting panicked residents know that the initial alert was a false alarm.
A monthly Tsunami Warning test was issued around 830 am by @NWS_NTWC . We have been notified that some users received this test message as an actual Tsunami Warning. A Tsunami Warning is not in effect. Repeat, a Tsunami Warning is not in effect #chswx #gawx #savwx #scwx— NWS Charleston, SC (@NWSCharlestonSC) February 6, 2018
The controversial alert came just three weeks after cellphones in Hawaii blared a bogus warning that the islands were under a ballistic missile attack.
In that incident, a Hawaii Emergency Management Agency employee pushed a wrong button during a test, triggering widespread panic. That employee has since been fired.
In Tuesday's incident, the National Weather Service said a technical glitch was to blame. The NWS conducts a monthly test but some mobile phone users received an alert that looked like a real warning.
AccuWeather, one of the services that passed on the warning, said in a statement that the information had been miscoded by the NWS.
"While the words 'TEST' were in the header, the actual codes read by computers used coding for real warning, indicating it was a real warning," it said. "We are continuing to work with NWS to determine why this coding was improperly embedded in its test alert system."
The chances of a tsunami hitting the East Coast are considered unlikely. Tsunamis are caused by earthquakes under the ocean and there are few, if any, along the East Coast.
Still, following the alert on Tuesday, residents panicked.
"Give enough false warnings, when the real one comes — no one will pay attention," one Twitter user posted. "Not a good practice."
Some managed to see the funny side, as another tweet read, "Nice to see that guy from Hawaii found a new job!"
Bob Strang, a security expert, said, "It's a wake-up call for people to be prepared if something were to happen. If you look and see an alert... what are you going to do?"