Tsunami Maps
Tsunami Hazard Map
The California Geological Survey has mapped Humboldt County's official Tsunami Hazard Areas. Map areas shaded in green are sufficiently high or inland to be safe in even the most extreme earthquake event. Map areas shaded in yellow indicate being at risk, especially for people closest to the beach or in low areas.
These maps show worst-case scenarios with an extra margin of safety, so communities are prepared for even the largest possible events. For the North Coast, this includes tsunamis from a magnitude 9 on the Cascadia fault, as well as smaller tsunamis from other sources. For most tsunamis, the water will not reach nearly as far inland.
The map boundaries are based on scientific inundation models but are extended slightly to make them practical for evacuation planning.
Schools in Tsunami Zones
In Humboldt, two schools are currently located within a tsunami hazard zone: Redwood Coast Montessori School's Manila Campus and Peninsula Union School in Samoa. These schools have plans in place for response to a local earthquake and tsunami. To learn more about the plans your child's school has regarding earthquake and tsunami safety, we encourage you to contact the school directly.
Printable Tsunami Hazard Maps
Download, print and find where you live or work on the below maps provided by the Redwood Coast Tsunami Work Group. If you are in the YELLOW area, plan a safe evacuation route on foot to the nearest green area.
The text description on these maps are an approximation and provides an overview. You can search for specific addresses using the Tsunami Hazard Area application above. If you need help understanding these maps, contact Humboldt County OES at 707-268-2500.
Tsunami Types
Near-Source Tsunamis
If you’re in an area where you feel the earthquake and it produces a tsunami, the ground shaking is your notification that a tsunami is potentially on the way. You may also observe an unusually large drawdown of water from the coast exposing the sea floor or even hear a loud roar.
For an event where you feel the earthquake, WALK out of the tsunami zone as soon as it is safe to move - don’t wait for an alert! Tsunami waves can arrive in as little as 10-15 minutes.
Do not enter or drive through tsunami hazard areas (including roads/highways in hazard areas) until officially informed it is safe to do so. Anticipate aftershocks.
Distance-Source Tsunamis
If the tsunami is generated in another location but is traveling towards your coastline, you may be notified by official alerts for a distant tsunami. This official warning can come from the Tsunami Warning Center or your the Humboldt County Sheriff's Office in the form of messages on TV and radio, sirens, audio messages from airplanes and even door-to-door contact.
Learn more tsunami safety tips, including how to prepare and what to do after a tsunami.
Tsunami Alerts
The Tsunami Warning System is controlled by the National Tsunami Warning Center in Alaska. Alerts are sent automatically via Wireless Emergency Alert (WEA), when an earthquake of magnitude 7.1 occurs in a coastal area.
Official tsunami warnings are broadcast through local radio and tv, marine radio, wireless emergency alerts, NOAA Weather Radio, and NOAA websites. They may also come through outdoor sirens, local officials, text message alerts, and telephone notifications. It’s important to know what the different alerts mean:
- Tsunami Warning - Take Action: A tsunami that may cause widespread flooding is expected or occurring. Dangerous coastal flooding and powerful currents are possible and may continue for several hours or days after initial arrival. Follow instructions from local officials. Evacuation is recommended. Move to high ground or inland (away from the water).
- Tsunami Advisory - Take Action: A tsunami with potential for strong currents or waves dangerous to those in or very near the water is expected or occurring. There may be flooding of beach and harbor areas. Stay out of the water and away from beaches and waterways. Follow instructions from local officials.
- Tsunami Watch - Be Prepared: A distant earthquake has occurred. A tsunami is possible. Stay tuned for more information. Be prepared to take action if necessary.
- Tsunami Information Statement - Relax: An earthquake has occurred, but there is no threat or it was very far away and the threat has not been determined. In most cases, there is no threat of a destructive tsunami.
Earthquake Alerts
Early Earthquake Warning System alerts are sent automatically by the Governor’s Office of Emergency Services (Cal OES) via Wireless Emergency Alert (WEA), when an earthquake of M 5.0 or higher hits anywhere in California.
Learn more about Shake Alerts and download the MyShake App to get push notifications for earthquakes M 4.5+.
Humboldt Alert
Humboldt Alert is an emergency notification sent out only after the appropriate agencies have confirmed with the Humboldt Sheriff’s Office of Emergency Services that there is a threat to public safety.