NORTH COAST, Calif. – A three-county coordinated tsunami warnings communications test is set to take place this Wednesday in Mendocino, Humboldt and Del Norte counties.

The test will take place from noon to 1 p.m.

This cooperative effort will include Mendocino, Humboldt, and Del Norte Counties as well as the National Weather Service and the California Office of Emergency Services, according to Lt. Shannon Barney of the Mendocino County Sheriff’s Office.

North Coast residents may see or hear test notifications broadcasted over the television and radio. Some residents may hear local tsunami sirens sound and observe the Civil Air Patrol flying along the coast with an audible message.

In Mendocino County people may hear tsunami sirens being activated in the cities of Fort Bragg and Point Arena, and they may get a test message in limited areas within these two cities, from a test of the county's emergency phone notification system, Barney said.

Registered Humboldt Alert users will receive a test notification during this time, in addition to listed landlines, according to the Humboldt County Sheriff’s Office.

The test coincides with Tsunami Preparedness Week on the North Coast.

A tsunami warning is the highest level of tsunami alert and is only issued when flooding of land that is usually dry is expected, the Humboldt County Sheriff’s Office said. They’re focused on a tsunami coming from far away.

If you hear that an official tsunami warning has been issued, move away from the beach and out of harbor areas. Tune into local radio or television stations for more information and follow the evacuation directions of local authorities, officials urged.

If a strong earthquake occurs close to our coast that lasts for 20 seconds or longer, a tsunami may follow. In this case, officials said there will be no time for an official warning to be issued. You must rely on recognizing the natural warning signs of a tsunami. An earthquake is the most likely natural warning sign that a tsunami is coming.

Other natural warning signs include the ocean water drawing back and exposing the seafloor, or hearing a loud roar from the coast. If you are in a tsunami evacuation zone and observe any of these warnings, move to higher ground or inland on foot as soon as possible. There may be as little as 10 minutes between the earthquake and a tsunami, officials said.

Officials said it’s also important to remember that surges may continue to arrive for 24 hours or longer.