If you hear outdoor sirens, have your television or radio feed interrupted, or get alerts on your phone warning of a tsunami on Wednesday morning, don’t worry! It’s just the annual Tsunami Warning Communications Emergency Alert System test. 

According to the folks over at the National Weather Service (NWS) in Eureka, the test will occur between 11 a.m. and noon on Wednesday, March 27, triggering the alert system for Humboldt, Del Norte and Mendocino Counties. 

“The test will simulate the dissemination of a tsunami warning for Del Norte, Humboldt, and Mendocino counties for a large tsunami wave originating from far away, such as in Alaska or Japan,” Ryan Aylward, a warning coordination meteorologist for NWS wrote in a recent press release. “Examples of events like this in the past include 1964 (Alaska) and 2011 (Japan) when tsunami waves hit our coastline from far away and caused damage.” 

The test will include alerts on radio and television broadcasts and activation of outdoor tsunami sirens in some areas. The NWS said that people on the coast might also hear test broadcasts from airplanes. The full wireless alert system for cell phones will not be a part of Wednesday’s test, but areas will also be testing reverse calling, email and texting systems.

Since this is only a test, there is no need to evacuate and no need to call emergency services. There’s no need to do anything, really. But the NWS recommends that you use the test as an opportunity to review what you would do if this were a real tsunami warning, starting with checking this map to determine if you’re in a tsunami hazard zone. 

“We recommend people take advantage of this test to review what you would do if you were provided notice that a tsunami wave will arrive in the range of 4 to 12 hours,” Aylward wrote. “Discuss your plan with family, friends, and coworkers. Confirm that you have multiple ways to receive the warning.”