Tsunami
A tsunami is a series of ocean waves caused by earthquakes, landslides, or volcanic eruptions. These waves can kill and injure people and destroy communities.
Tsunamis strike as fast moving walls of water that flood, drain, and reflood the land for hours. Tsunamis can flood more than a mile inland.
The 2011 Tōhoku Earthquake in Japan caused strong, damaging currents and sudden fluctuations here in California. These currents and waves led to tens of millions of dollars in damage along the California coast. Some docks were damaged, several vessels sunk, and sediment was deposited in various areas along the coast.
While the City of Oakland was spared from major damage in this tsunami, this event is a reminder that tsunamis are a threat to the entire Bay Area.
What's the Difference Between a Watch and Warning?
Emergency messages about tsunamis come in different alert levels. Learn what each type of alert means and what you should do.
Tsunami Warning
What it Means:
A tsunami warning indicates the highest level of threat to the City of Oakland. This means that a tsunami is imminent with a high threat of flooding and dangerous currents.
What to Do:
If you receive a Tsunami Warning, get to high ground or move inland immediately. Follow evacuation routes.
Tsunami Advisory
What it Means:
A tsunami advisory is the second highest level of threat. This means that there are strong currents and dangerous waves in or near coastal waters.
What to Do:
If you receive a Tsunami Advisory, stay out of the water and away from the shore.
Tsunami Watch
What it Means:
A tsunami watch means that a tsunami is possible. Arrival time may be hours away.
What to Do:
If you receive a Tsunami Watch, prepare to evacuate and continue to monitor alerts. The alert level may change as the waves approach the City of Oakland. Gather your belongings and emergency supplies and be prepared to evacuate if the alert level changes.
Tsunami Information Statement
If you receive a Tsunami Information Statement, no action is needed at this time. Officials do not anticipate any impact for your location.
If conditions change, officials will release another alert.
Tsunami Hazard Zone Map
Click here to view the Interactive Oakland Hazard Mapper
What to Do
Before
Before a Tsunami
Plan and Prepare
- Be prepared with an emergency plan and communications plan.
- Know whether or not you're in a tsunami hazard zone.
- Organize important documents into an easy to find and carry format. Consider a waterproof container or storing documents on an encrypted flash drive or portable hard drive.
- Sign up for alerts so that you can stay informed. Visit the stay informed page to learn about the emergency siren and hear a sample.
- Know your evacuation routes and where to go for higher ground.
- Don't drive? Ask a neighbor now if they can help. Coordinate a plan with your household and your neighbors.
Know the Warning Signs for Local Tsunamis
An underwater earthquake in the Bay Area can cause a tsunami. If that happens, there may not be time for alerts. If you're in Oakland's tsunami hazard zone, evacuate immediately after the shaking is over if you experience any of the following:
- Strong shaking that lasts 20 seconds or more.
- A loud roar from the ocean.
- Water suddenly pulling away from the shore.
During
During a Tsunami
If you are advised that there is a Tsunami Advisory or Tsunami Warning, take action immediately.
During a Tsunami Advisory, stay away from the shore and do not enter the water. If you are in a tsunami hazard zone, pack your belongings in your car so that you are ready to evacuate if conditions worsen.
During a Tsunami Warning, evacuate immediately. Move to high ground or inland away from water.
The Shaking Is Your Warning
Remember, a major local earthquake may cause a tsunami quicker than an alert can be sent out. If you live in a tsunami evacuation zone, the shaking IS your evacuation warning.
Evacuation Information
If you are inland and not in a designated tsunami hazard zone, stay off the streets and highways. Help reduce traffic so that your neighbors in the hazard zone can get out. If advanced notice is possible (such as a tsunami originating farther away), the City of Oakland may evacuate in stages so that people in the most danger can get out first.
See Additional Information about Evacuations
After
After a Tsunami
Stay away until it is safe.
Tsunami waves can last for many hours, even after the first one hits. Strong aftershocks can prolong the impact of tsunamis.
Wait for official instructions before returning to the tsunami zone. Damaged areas may stay closed for a long time due to flooding, unsafe buildings, or contamination.
If your home or other property was hit by waves, make sure to walk around your property to check for hazards. Some items you should examine include:
- Making sure your home is still on its foundation
- Smell of gas, sounds of hissing, or other signs of a gas leak
- Toss all garden produce if there is a risk of contamination
- Clearing debris and fallen tree branches so that it doesn't clog the storm drains
- Check your roof for damage
- Signs of water intrusion into your home (examples include damp carpets, water stains inside your home, warped floorboards, or musty odors); if not properly addressed, water intrusion could lead to damage you can't see like rusted pipes, mold, or dry rot