The Next Wave in Tsunami Warnings in Humboldt

Tsunami siren. [Stock photo of a typical siren]

Imagine you are walking along the ocean shoreline in our county, and the ground starts to shake violently.   Several minutes later, your phone receives an alert telling you a tsunami is likely.   What do you do?  Are you in a tsunami zone?

Shortly after a 7.0 magnitude earthquake struck off the Humboldt County coastline on December 5, 2024, an emergency tsunami warning was sent to 5 million cell phones along the California coast.  Alerts went to phones outside the tsunami zone, including inland communities such as Redding.

Maps, generated by the National Weather Service and issued during the tsunami warning, implied that the tsunami zone extended to a 2,000-foot elevation.

Confusion resulting from this map led to a mass exodus from areas that were not at risk. Traffic on Highway 101 through Eureka came to a standstill.  Emergency vehicles could not get through.

Humboldt residents are very aware of their vulnerability to earthquakes and tsunamis, but when an earthquake occurs and is sufficiently violent to create tsunami waves, alerting those who are likely to be affected and providing accurate information to allow a safe reaction remains problematic.

The Civil Grand Jury Report The Next Wave in Tsunami Warnings in Humboldt was published…on the Humboldt County website Civil Grand Jury | Humboldt County, CA – Official Website, and addresses these concerns.

Among the Grand Jury’s Findings

• Humboldt County tsunami sirens are costly, lack funding, and nearly all are non-functional, leaving large tsunami zone areas without siren coverage.
• Alaska-based federally operated tsunami alert systems have historically been targeted to large areas of the west coast, resulting in local false alarms, confusion and needless panic.
• “Blue line” pavement markings, used in Oregon and Washington, that indicate “Leaving Tsunami Zone” have proven effective and economical in drawing public awareness to where safety lies in the event of a tsunami
• Current Humboldt Alert wireless messages are targeted to residential addresses rather than the physical address (geolocation) location of the person’s phone. This can result in people missing an alert during a tsunami event.

Among the Grand Jury’s Recommendations

• Humboldt County should publicize that Humboldt County’s outdated siren system will not be replaced or expanded.
• The City of Eureka City should apply for eligible grant funding for “blue line” pavement markings to be installed.
• Humboldt County Office of Emergency Services should investigate funding to install a locally-controlled wireless alert system.
• Humboldt County Office of Emergency Services should implement geolocation on its current wireless alert system and, if the system does not have that ability, research other systems which provide geolocation capability.

Media contact: Grand Jury Foreperson, Kathleen Sartorius at [email protected]

Signs-GJ release 6.9.26