Last week, just after an 8.8 magnitude earthquake violently shook the eastern edge of Russia, Southern Californians were warned to gird for possible impact: a tsunami was headed across the ocean, taking aim at the shores of California.
Across the region, state and local officials quickly deployed. They closed beaches and patrolled harbors, warning people to get out of the water and stay clear of the shoreline. Public safety agencies urged calm while offering imprecise predictions of exactly what might occur in a few hours when the waves arrived. All of that helped induce and feed general anxiety in folks who live and work along the coast, making them wonder: How serious is this?
As it turned out, little damage was reported across the state.
The disconnect between the one of the most powerful quakes ever recorded on Tuesday, July 29, thousands of miles away, and the relatively tiny waves it generated along California’s coast highlight the dilemma faced by experts whose job it is to keep people safe when real dangers eventually show up.
Among the decisions they weigh is how to ensure the general public takes new weather events and alerts seriously, even after past ones had little impact in their cities.
Costas Synolakis, director of the USC Tsunami Research Center, helped develop and test technology in 2006 that he says could help weather experts make more targeted warnings specific to smaller regions. For instance, he said, an evacuation order last week that caused traffic gridlocks and panic after the tsunami warning in Hawaii, despite minimal impact, may not have been necessary if technology was used to make more precise estimates of impact.
“They have the technology to actually do much more specific warnings, but they are not implementing it yet,” Synolakis said last week. “They are very, very conservative.”
If people continue to be alerted or evacuated unnecessarily during future tsunamis, Synolakis said, it’s possible they won’t act quickly when there’s a true threat to safety. It’s a particular concern now, he said, as more people have experienced “alert fatigue” after getting frequent alerts through their cell phones.
“Unless you have very targeted warnings,” he said, “people will start eventually not heeding them.”
On social media, some people opined that that safety tips and alerts may have been overblown. Sebastian Westerink, a meteorologist with the National Weather Service, said the region experienced the wave height that forecasters predicted, which could have caused more damage if people didn’t heed official warnings and stayed at area beaches.
“For people to not have experienced the impact is the whole point,” he said. “More people would have experienced the impacts if they were at sea or in the water.”
Worry among others may have come from a misunderstanding of what a tsunami looks like, said Patrick Lynett, a civil and environmental engineering professor at USC.
Tsunami waves between one and three feet, as was expected across most of the California coast, don’t bring a movie-style, large crashing wave that spills over to streets or floods cities. Instead, they look more like a rising tide, Lynett said.
Lynett said officials made accurate predictions of wave heights across the West Coast but may look into whether or not there were overestimates of the tsunami’s impacts in Hawaii. The governor called a statewide emergency and residents across the state evacuated their homes, but after the tsunami hit, there were no reports of significant damage.
The possible overestimation could be due to a change in the direction of the tsunami’s energy. A tsunami usually focuses most of its energy in one spot, but if the storm changes while traveling, its focus can shift, as well, Lynett said.
“The damage was relatively minor,” Lynett said. “It was a large tsunami. We might have just been fortunate.”
It’s understandable that people are confused and even annoyed when a weather alert suddenly alters their plans, especially when they later feel the weather event had little impact in their area, said Dave Snider, a tsunami warning coordinator with the National Oceanic and Atmospheric Administration.
But officials have to alert the public, he said, based on the information they have and the predictions they’re able to make.
The initial alert experts make is based on the size of the earthquake and its location. Within about 30 minutes to an hour, they gather information about underwater impacts and if there’s enough water to move. At that point, he said officials can only predict if there’s a possibility of a tsunami.
Next, they turn to DART buoys, or Deep-ocean Assessment and Reporting of Tsunamis, that monitor if a tsunami wave passes the buoy. If there’s a wave, experts measure the information gathered from multiple buoys before creating a more localized forecast for various communities.
In that time, the Southern California area received a tsunami watch, warning of the possibility of a tsunami in the region, which was later upgraded to an advisory, meaning a tsunami that could pose a danger to people or structures on or near the water was likely. Some cities closed beaches, and officials warned community members to avoid harbors and piers.
“All that is happening over hours and it’s not immediate,” Snider said, “and it’s certainly not something that we can know perfectly in the moment of sending that very first alert message when the earthquake occurs.”
Snider said he always worries that people may ignore alerts and warnings if they’ve seen previous weather events have little impact in their area. Complacency in weather events could harm or kill people, he said.
After the tsunami, he said NOAA is gathering information from community partners to review the alert system and identify areas for improvement. In general, Snider said, NOAA has been working on improving and modernizing its tsunami alert system and rebuilding the tsunami.gov website, which could be ready by the end of the year. He hopes the changes help the general public better understand the threat of a tsunami and the steps they need to take from the moment they receive their first alert from weather officials.
“You have to be able to use that information when you look at it the first time,” he said. “There’s a lot of what we do today that’s built around the science, but it hasn’t clearly communicated the problem to put that into terms and methods that the public can understand in that moment of surprise, panic and necessary action.”