Smartphone users may have received the alert as a notice on their phones.
Once a user swiped into the story, it became apparent this was only a test.
The alert was issued by NOAA and was sent to users on the Gulf Coast and East Coast.
The National Weather Service Tsunami Warning this morning was a TEST. No Tsunami warning is in effect for the East Coast of the U.S.
— AccuWeather (@accuweather) February 6, 2018