Tsunamis

A tsunami is a series of large, strong waves caused by earthquakes, underwater landslides, volcanic eruptions or asteroids. A tsunami can kill or injure people and damage or destroy buildings and infrastructure as waves come into land and go back out. Tsunamis can:

• Travel 20-30 miles per hour with waves 10-100 feet high.
• Cause flooding and disrupt transportation, power, communications, and the water supply.
• Happen anywhere along the Marin Pacific or bay coasts.

Know Your Risk. Find out if you live, go to school, or work in a tsunami inundation area. If your community has road signs identifying tsunami evacuation routes, become familiar with them — these are known paths to higher ground.

Learn the signs of a potential tsunami. A long-lasting, strong earthquake, a loud roar from the ocean, or unusual ocean behavior, such as a sudden rise or wall of water or sudden draining of water showing the ocean or bay floor, could all be signs of a tsunami.

Stay Informed. Sign up for AlertMarin, Marin County’s alert and warning system. The AlertMarin system is how authorities will communicate with you about the need to evacuate to higher ground.    

Prepare a go-bag. Gather essential items in case you need to evacuate. Each person and pet needs their own bag with their personal items and important documents.

Make a Plan. Know two ways out of your neighborhood to get away from the coast and to higher ground.  Identify a meeting place outside of the tsunami inundation area for your household to meet at if you need to evacuate and can’t get ahold of your loved ones.   

Evacuate immediately to high ground. When the shaking from an earthquake stops, if there are natural signs or official warnings of a tsunami, move immediately to a safe place as high and as far inland as possible. Listen to the authorities, but do not wait for tsunami warnings and evacuation orders.

If you are outside of the tsunami hazard zone and receive a warning, stay where you are unless officials tell you otherwise.

Stay Away from the Water. Never go to the bayshore, coastline, creeks, harbors, piers or near water to watch the tsunami waves. Even small tsunami waves can have a dangerous and powerful current and they can arrive very fast.   

Stay Informed. Check the Marin County Public Emergency Portal for local up-to-date information. Listen to the radio for important information and instructions. Aftershocks, which often follow large earthquakes, can cause damage too.  

Check for Injuries. Make sure you and those around you are okay. Call for medical help if a true emergency.  

Avoid Floodwaters. A tsunami creates flood water can be dirty and dangerous with strong currents and hidden hazards. Never drive through a flooded area.  

Stay Informed. Continue to monitor your trusted sources for updated information and instructions.  

Help Your Community. Check on neighbors, especially those who might need extra help like older adults or people with disabilities.