San Diego tsunami evacuation signs: Do you know what to do if one hits?
SAN DIEGO (KSWB) — If you have been to the coast anywhere in San Diego County, you might have noticed the tsunami evacuation route signs with an arrow pointing inland. But what do they mean? Are you prepared if a tsunami were to hit the San Diego coast?
Locals are likely very familiar with the signs, but as a newbie to the city, it will make you stop and ask the question — what do they mean?
With the earthquake that shook coastal areas from San Diego to Los Angeles County on Martin Luther King Jr. Day, and the recent series of major earthquakes in Japan that caused high-level tsunami alerts for Japan and parts of North Korea and Russia, it brings the topic to mind even though NWS says no tsunami warnings were issued for San Diego.
The tsunami evacuation route signs just have an arrow that points inland. But in the event of an emergency, are you prepared? Let’s dive in to what the signs mean and the tsunami evacuation map the County has online.
What are tsunamis?
A tsunami is a series of waves created by disturbances from earthquakes below or near the ocean floor, or from other disturbances like landslides, volcanic eruptions, or even by impacts from comets, asteroids or meteorites.
There are two sources of tsunamis — remote and local.
Remote tsunamis are the most frequent to hit California, and are generated by earthquakes off the coasts of Japan, Alaska, Hawaii and Chile.
Local tsunamis are generated off the coast of Southern California and are dangerous because they can hit the coast very quickly, usually in less than one hour.
San Diego tsunami warnings/advisories
San Diego County says only four locally generated tsunamis have been reported since 1800.
The most significant remote tsunami to hit Southern California was in 1960 when a 9.5 magnitude earthquake off the coast of Chile caused a tsunami with 4 foot waves.
In recent years, a February 2010 earthquake off the Chilean coast generated tsunami waves and triggered a Tsunami Advisory for San Diego County and the entire California coast. The tsunami waves did reach the San Diego coast and caused tidal draw back and surges, according to the City of San Diego, but did not cause significant damage.
NOAA says areas with Pacific and Caribbean coastlines are at the greatest risk for tsunamis. Most tsunamis are less than 10 feet high, but they can reach heights of up to 100 feet.
It only takes six inches of fast-moving water to knock over an adult, and just two feet of fast-moving water to carry away most vehicles, according to NOAA.
Luckily, for anyone who lives here knows, tsunamis are rather rare in Southern California. In the past 150 years, only 13 tsunamis have been large enough to cause damage in San Diego County. However, with 70 miles of coastline in San Diego County, tsunamis remain a possible threat.
Just in 2022, San Diego and the entire West Coast was under a tsunami advisory after a volcano erupted in the Pacific Ocean.
What to do
When a tsunami is imminent, evacuate beaches and low-lying coastal areas. Beaches, lagoons, bays, estuaries, tidal flats and river mouths are the most dangerous places to be. Some good news, it’s very rare for a tsunami to reach more than a mile inland.
An important fact — the first tsunami surge is usually not the highest. The largest surge can come hours after the first wave hits.
The California Emergency Management Agency has put together a list of things to do to survive a tsunami. If you feel an earthquake nearby or know a tsunami wave is going to hit, take cover.
If inside, get behind a table or large object, cover your head and neck, and hold on. If outdoors, move away from beach cliffs, trees, signs and anything else that could be picked up as debris by the wave.
The second step is to move to higher ground as soon as you can if you are in the evacuation area; don’t wait for an official tsunami warning.
The third step — remain on higher ground until the all clear is given by officials. If you are outside of a tsunami hazard zone, you are safer staying where you are.
Click here for a list of evacuation maps for San Diego County cities of Carlsbad, Chula Vista, Coronado, Del Mar, Encinitas, Imperial Beach, National City, Oceanside, City of San Diego, and Solana Beach.
If no maps or signs are available, it is advised to head away from the coast. Get to higher ground or head one to two miles inland.
If you are in a boat in the harbor when a tsunami is coming, try to leave the boat to get to higher ground.
If you are at sea during a warning, it is advised to move to a safe distance and stay away from harbors until the threat has passed. The U.S. Coast Guard would issue urgent marine information broadcasts on marine VHF radio’s channel 16.
How to tell if there is a tsunami coming
Water receding to the point the sea floor is exposed is a sure sign of an impending tsunami. Other signs to look out for — the ocean might even roar and the ground can shake.
A wall of water is also a dead giveaway that you need to leave the coast.
Be prepared
Be aware of the tsunami hazard zones and the evacuation map in areas you frequent. Create an evacuation plan with your family. Sign up for alerts. Have a emergency kit prepared, which could be used for any form of emergency.
Get alerted
The most obvious way to be alerted is through official channels — radio, TV, phone, NOAA weather radios, or you can sign up for emergency alerts with Alert San Diego. In the event of an official tsunami warning, it would be broadcast on all emergency alert channels.
In 2022, The California Department of Conservation updated tsunami hazard area maps for all 20 of the state’s coastal counties. All San Diego residents in hazard areas should also have received guidance from the city on preparing for a tsunami.
You can visit NOAA/NWS U.S. Tsunami Warning System for real-time alerts/threats. You can also visit California Geological Survey’s interactive earthquake map.
For the latest news, weather, sports, and streaming video, head to FOX 5 San Diego.
