A server error Wednesday caused Seaside, Oregon, residents to receive a message warning of an impending tsunami. They quickly learned it was a false alarm.
Seaside and other coastal towns regularly test warning systems that are designed to alert residents of potential tsunamis caused by off-shore earthquakes.
But Wednesday's test went awry.
"We heard from several people through our social channels that they were moving to higher ground and/or making preparations to leave from low lying areas," said Jon Rahl, Seaside's public information officer.
Other people said on social media said they were confused by the message, which came around the same time as a regularly scheduled "test" for the month of January.
"At first I panicked but then I thought, what are the odds of having an actual tsunami on the same day and hour as the scheduled tsunami test?" Seaside resident Sharon Johnson wrote on Facebook.
Rahl said an effort to test the system is what triggered the false alarm.
A computer crash in December had affected the server that manages the messages. While the city had thought fixes for that crash were in place, an error in the system caused the real tsunami warning to go out.
The message told residents they had around four hours until a tsunami hit. But Rahl said most people were informed quickly that they did not need to move to higher ground.
"We were aware of the incorrect message within a few minutes and a message through our social and Nixle channels explaining that this was indeed just a test and that the message was erroneous went our shortly after that," Rahl told OPB.
Nixle is a software that sends emergency alerts to people who register their phone number.
Technicians were able to quickly fix the problem Wednesday, Rahl said, and the city does not expect a similar error to happen again.
There may be a silver lining for the false alarm. Several residents said it was a good chance to talk about preparing emergency kits before a major Cascadia Subduction Zone earthquake hits.