The Tsunami that wasn't: Lessons learned

It was an exciting morning.  I just happened to be outside talking to a buddy whose tsunami knowledge was unknown to me when his phone went off about 10:45 am.  I got nothing on my phone, but he started making a plan since he knew a "warning" is the highest level of four notices that are issued.  Listening to him, I was concerned for the coastal areas covered in the warning; from the area of the 7.0 undersea earthquake off Ferndale down to Davenport on the PCH.  I was skeptical that it would be an issue here on the west side of B'game.  Nonetheless it was time to turn on the local TV news station that was in Breaking News mode.  There was a second quake north of Sacramento that registered a 6.0, the BART tube was shut down and SFO was landing flights as normal while noting the runways are only 13 feet above sea level.

The warning was in effect until 11:49 am-- an hour after the quake hit.  My knowledgeable buddy took off--I didn't ask where, but he mumbled something about "uphill".  The TV experts from SFFD, National Weather Service and some quake center were talking Go-Bag and getting up to 100 feet of elevation.  Traffic on eastbound 92 was bumper to bumper.  I was still skeptical of any tsunami squeezing through the Golden Gate, wrapping around the Bay and pushing water past maybe our Bayfront.  There's a reason Laguna Ave. is named Laguna Ave.  After watching the YouTube documentary on the Japan tsunami of 2011 my friend recommended, a second thought or two has crept in.

I have to wonder why the SMC Alert didn't hit my phone until 11:49 am, an hour after the quake and then was deemed not a danger at 12:10 pm?  It turns out that a 7.0 quake, while big in town, isn't considered to be big enough to cause a major tsunami.  Is there such a thing as a minor tsunami?  Let's hope SMC alert and the quake shake apps are working as designed.  

Comments

[Jennifer Pfaff]

'SAME!

First I thought all the whistles were certainly a mistake, and then looking at all the RED areas, I started wondering, Where To??

Even Hillsborough was red (?), so where would be deemed safe? That was about the time when they were about to start evacuating an elementary school in Pacifica. Honestly, it seemed to me the regular old TV news was more up to date than all the I-phone sirens and tsunami of news.

I think Burlingame station is only about 14 ft. above sea level-- not very high. A friend of ours got stuck on BART and had to be rescued in Daly City and driven over the bridge to get to a meeting in Berkeley. We wondered if the bridge would be shut down for some odd reason. Chaos somewhat reminiscent of the 1989 quake, but we never felt a thing--who did?!? Very odd.

'Was very happy when the graphic of white replaced all the ominous red areas. I hope they can get a bit more refined on the mapping the next time, because it sure didn't look like they thought any place was "safe", at least according to the maps shown today.

[Joe]

The Merc is asking questions:

It was a typical sunny Thursday morning — and suddenly messages popped up on millions of cell phones across the Bay Area and Northern California: “Tsunami warning … you are in danger … move to higher ground or inland now.”

The rare bulletin at 10:49 a.m. from NOAA, the National Oceanic and Atmospheric Administration, came after a 7.0 earthquake off the Humboldt County coast. It caused police to scramble and local officials to set off tsunami warning sirens along the coast and around San Francisco Bay. Berkeley ordered evacuations along its waterfront. BART stopped trains. Anxiety levels jumped.

Then an hour later, it was cancelled.

“They were being cautious,” said Amy Williamson, a research scientist at the UC Berkeley Seismology Lab. “They would rather have a warning and retract it an hour later than to have no warning at all and have people near the coast line suffer the consequences.”

But on Thursday, the 7.0 quake was located close to shore, only about 40 miles from the Humboldt County coast. There are no islands or buoys between the epicenter and the land.

“Because this quake was so close and sufficiently large and shook for a long enough time, the warning was issued out of an abundance of caution,” said Brian Garcia, warning coordination meteorologist for the National Weather Service’s Bay Area office. “If we don’t issue a warning and it generates a tsunami, then you are putting people’s lives at risk. We want to make sure people don’t die from a tsunami.
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So the bottom line is it was close to the coast, fairly big and the alerts went out quickly. It also showed how screwed we will be if there is a 9.0 like Fukishima close to the coast. Just another day in paradise.

[Joe]

Here's one more snippet from the national news coverage:

At least 5.3 million people in California were under the warning, which covered over 500 miles of coastline from Oregon to the San Francisco Bay Area. Many were urged to evacuate or move to higher ground on short notice over fears that a dangerous surge of water would strike just after noon local time.

In Pacifica — just south of San Francisco — some surfers were spotted flouting advisories and recklessly heading straight for the coastline. They stood watching the waves as friends snapped photos of the scene.

Seismology experts have been cautioning for years that California — which is bisected by the volatile San Andreas Fault Line — is overdue for “the big one,” a quake which could bring about devastation similar to the 1906 disaster.

[resident]

Does the sheriff department run the SMC alert thingy? Asking for a judge.

[Joe]

Ha. Good question. Here is why there was no tsunami yesterday:

Thursday’s quake occurred along a restless region where two tectonic plates, the Gorda and Pacific, converge. It’s called the Mendocino Fault and is considered part of the Cascadia subduction zone that extends farther north along the coast. This area is known for frequent earthquake activity due to its complex plate interactions.

A tsunami was not triggered, as feared, because it was a “strike-slip” fault where two of Earth’s tectonic plates slid past each other horizontally. This resulted in minimal vertical displacement of the seafloor. All of the Bay Area’s faults, such as the Mendocino Fault, are strike-slip faults.

Japan’s 8.9-magnitude earthquake that set off a devastating tsunami in 2011, sending walls of water washing over coastal Japan, was very different. It occurred in what is called a subduction zone where one of the Earth’s tectonic plates slid beneath another.

[Joe]

The Chronicle managed to do some real reporting on the confusion surrounding the tsunami that wasn't. Headline:

Mistaken message on tsunami danger sent to thousands in Bay Area, highlighting region’s messy response

The San Mateo County personnel did not come off looking very competent. Here are some snippets:

Ryan Reynolds, program services manager with San Mateo County’s department of emergency management, said in an interview Friday that the X post may have resulted from a glaringly simple mistake: Someone in his office acted on a weather service tsunami bulletin that had ended the alert for Hawaii, not California.

“I think that’s a distinct possibility,” Reynolds said. “I cannot say for sure. I don’t know. These things are happening very quickly. And that’s why we’re continuing to push that and get that information correct.”

San Mateo County issued its first warning to residents at 11:16 a.m. on its X account. Six minutes later, it mistakenly issued the threat cancellation.

Reynolds told the Chronicle that his agency had called the Monterey office of the weather service, which said it did not expect San Mateo County to get hit hard by a potential tsunami because it had few low-lying coastal areas and the worst waves were expected to hit farther north.

After someone likely mistakenly read the wrong message from the tsunami center website, the department double-checked on a phone call with the Governor’s Office of Emergency Services, known as Cal OES, to determine whether the office could verify the tsunami warning had been cancelled.

“The exact wording they used is, ‘That’s what we’re hearing,’” Reynolds said.

Amy Palmer, spokesperson for Cal OES, said that her agency’s “public messaging accurately carried the tsunami warning information for the duration of the tsunami alert and accurately conveyed the timing when it was canceled.”

However, the Chronicle was unable to verify with Cal OES Reynolds’ account of the conversation.

After the mistaken X post, Reynolds’ office called the Monterey branch of the weather service, which said the warning was still in effect.

At 11:31 a.m., San Mateo County corrected its error: “UPDATE AGAIN: National Weather Service has reissued the tsunami warning. Expected arrival at 12:10 p.m. AVOID beaches and coastlines. Move to high ground immediately! Updates to follow.”

The federal agency had not “reissued” the warning — it had never canceled it to begin with. Reynolds said that at this point, the mistake had been made and we “used the term reissuance to try and avoid conflicting information.”

A county spokesperson, Michelle Durand, said, “We used the term ‘re-issue’ because at that point in time it appeared to be just that, and also we felt it might be less confusing for residents who might not realize this was a new post.”

Finally, at 12:08 p.m., San Mateo County correctly alerted the public that the tsunami warning had been canceled. In retrospect, Reynolds saw learning opportunities.
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There are definitely some "learning opportunities" here, but will they be pursued?

[Joe]

Well, here is another warning that I didn't get!! I hear there was perhaps a "mini-tornado" in B'game as well as this one in Scotts Valley

Earlier that day, NWS radars indicated strong winds off the coast of San Mateo, meeting conditions that would trigger a tornado warning for San Francisco and northern San Mateo County. The warning, which was the first-ever in San Francisco, went into effect around 5:54 a.m. before being lifted about 20 minutes later. Hefty wind gusts knocked down trees and power lines across the city, blocking major roadways and streets and shocking residents.

[Peter Garrison]

Didn’t get the notification but our neighborhood got smacked.

I lost three trees and debris was scattered from other properties.

Big cypress down across Hillside onto neighbor’s fence (home?).

Giant redwoods on Los Robles down.

PG&E working fast. Heard chainsaws about 30 minutes after the windstorm/tornado.

[Joe]

Check out this CYA message. Never heard this detail before. Will anyone get fired after the last fiasco? Doubt it.

As a reminder, January 1, 2025 (New Year’s Day) falls on the first Wednesday of the month. On every first Wednesday at 10 a.m., the County conducts a test of the Coastal Tsunami Warning Sirens at full volume. Many residents may have never heard the sirens tested because they are not in the area at the time.
San Mateo County's coastline is equipped with 8 Tsunami Sirens: 3 in Pacifica, 4 along the mid-coast, and 1 in Pescadero. These sirens are activated only when a tidal surge from a seismic event is imminent. They serve to let anyone in the Tsunami Hazard Zone know to head to high ground immediately. This can be done by walking or taking a short drive away from the water.
To see if you live in the Tsunami Hazard Zone, check the yellow zones on the map linked here: Tsunami Hazard Map. The high ground is marked in green.
The sirens are designed to be heard outdoors in Hazard Zones, but may also be heard in non-hazard areas. Therefore, it is important to know in advance if you live or work in a Tsunami Hazard Zone. During an actual emergency, the website may get overloaded, so look up your area on the Tsunami Hazard Zone Map here: Tsunami Hazard Map

If you're in the area at 10 a.m. on Wednesday January 1, 2025, please take the time to familiarize yourself with the alert tone of the Tsunami Siren by listening to the live siren or to this audio: Tsunami Siren Wail Sound. This sound is different from the other types of sirens you hear from emergency vehicles or the “Hi-Lo Time to Go” sirens which are strictly used when an area needs to evacuate.


Regardless of the hazard, we encourage you to prepare your family with an all-risk emergency plan and have a Go-Bag ready to evacuate at any time. Be sure to include environmental hazards like weather, seismic events, and wind-driven fires in your planning. Understanding your potential alerts and hazards—whether or not they directly impact your area—can help you better prepare.

Summary: This TEST of the Tsunami Sirens is exactly the way the siren will sound during real danger of a tsunami approaching. The test is to let people know what the sirens sound like, and to ensure the equipment is working.
During an actual emergency, when you get an alert or hear the Tsunami Siren, it is best to grab your Go Bag and walk to higher ground – away from the water – to safety.
Wait until you get the “all clear” from officials before returning to lower areas.

Do you live or work in a low-lying area? Look up your address now: Tsunami Hazard Map.
May we enter this new year happy and prepared!