Tsunami warnings and watches along the west coast of the U.S. and Canada were canceled Tuesday morning as the potential risk subsided, but experts say communities remain vulnerable to future disasters and residents must be prepared for a cataclysmic wave in the future.
According to the U.S. Geological Survey, the alerts were triggered by a magnitude 7.9 earthquake in the Gulf of Alaska, about 175 miles southeast of Kodiak and at a depth of 15 miles. It was one of the largest on record in that region, according to the Alaska Earthquake Center.
Sirens blared in Kodiak and other coastal towns soon after the 12:31 a.m. quake, leading to evacuations to higher ground and emergency shelters. All Alaska warnings were canceled around 4 a.m. after waves no higher than one foot were recorded.
Tsunami Watch alerts were initially issued for the entire coasts of California and Oregon and the outer coast of Washington. About two hours after they were issued, they were canceled because “additional information and analysis have better defined the threat.”
Still, officials in some coastal areas warned residents to stay away from the shores. The San Francisco Department of Emergency Management urged citizens to avoid the coastline for 12 hours due to potentially strong and dangerous currents.
Residents may be frustrated that they were riled out of bed in the middle of the night by wireless alerts for nothing, but Eric Holdeman, a former Washington state emergency management official, said it is better to warn than not.
“There will be people who complain it ended up being a six-inch wave and they’ve been inconvenienced by it…but if it’d been a 15-foot wave, they’d have been much more inconvenienced by it,” he said. “People need to accept the imprecise nature of these warnings.”
The brief period of warning provided a test of local, state, and federal emergency procedures that are frequently drilled but rarely get unplanned real-world practice.
As with all natural disasters, preparedness plans for tsunamis are typically focused on mitigating the damage and loss of life during and after the event, but there are significant differences between preparing for a tsunami and other disasters.
“There are a lot of things you can do that are parallel…. For a tsunami, there are special considerations,” said Jason Ballmann, communications manager for the Southern California Earthquake Center.
A tsunami is a series of ocean waves generated by an event that displaces water like an earthquake, volcanic eruption, or landslide. The waves can bring walls of water dozens of feet high to shore, but even smaller waves have the potential to cause significant damage.
Tsunamis can be produced by local or distant events. In the case of a local event, officials may only have only minutes to warn residents, but if a distant event causes waves, they may know the water is coming hours in advance.
“A tsunami is unique in a couple of respects,” said Mike Angove, manager of NOAA’s Tsunami Program. “Number one is how catastrophic the impact can be, and then you combine that with the fact that you really have no lead time.”
Because of that, NOAA works closely with local officials to develop mitigation plans.
“We really try to attack it on two fronts,” Angove said. “We, on the one hand, are trying to improve our forecasting warning capability…and then on the other side, trying to match that with preparedness on the state and local level.”
Waves large enough to devastate communities rarely reach land, but they have had substantial impact several times in the last two decades.
A magnitude 9.0 earthquake in 2004 sent waves up to 100 feet high toward Indonesia, Thailand, India, Sri Lanka, and the Maldives, killing 283,000 people and displace 1.1 million others.
In 2011, another 9.0 magnitude earthquake slammed northeastern Japan, causing a tsunami that set off a nuclear accident at the Fukushima Daiichi Nuclear Power Plant. Nearly 16,000 people were killed and, as of June 2016, 2,500 were still missing.
Effects of the 2011 tsunami were felt as far away as California, where waves caused hundreds of millions of dollars of damage and killed a man trying to take photos at the mouth of the Klamath River.
Following the 2004 tsunami in Indonesia, Sen. Dianne Feinstein, D-Calif., asked the Government Accountability Office to assess federal and state preparedness. The review found that many warning systems and emergency plans were out of date or limited in their effectiveness.
“That was an important report for us,” Angove said.
NOAA has since improved its sensing infrastructure and its ability to model tsunamis in real time. It has also worked to ensure that its directives are digestible and actionable at the state and local level.
“We take those reports very seriously and we made a lot of effort to address the concerns raised by the GAO,” Angove said.
Massive disasters like those seen in 2004 and 2011 may lead officials to reevaluate their plans, but Brad Alexander, a spokesman for the California Office of Emergency Services, said coastal communities have been well aware of the danger since the 1964 tsunami.
“I think it’s been a growing process since the 50s and 60s,” he said.
Technology has made the warning process easier in recent years. With wireless emergency alerts, reverse 911, and social media, the threat advisory spreads quickly.
“Once you get that notice or alert, people are calling people,” Alexander said. Even if the alert itself does not wake you, it is likely family or friends who did hear it will be calling.
According to Patrick Corcoran, a hazards outreach specialist at Oregon State University and the Oregon Sea Grant program, tsunamis remain an abstract concept for many people in the U.S. because, unlike earthquakes, they have never seen one.
“It’s hard to take something seriously that you haven’t experienced, nor your parents or your grandparents,” he said.
The last massive earthquake along the Cascadia Subduction Zone on the west coast was 318 years ago this week, creating a tsunami that was documented in Japanese history and in Native American legends, but Corcoran said it is human nature not to take the threat of such rare events seriously enough.
“The vast majority of my job is convincing people that something that happened 41 times in thousands of years is going to happen 42 times,” he said.
Though they are generally seen as facing much lower risk, some eastern cities and states have developed tsunami mitigation plans as well.
A 2014 New York state planning document states that the closest occurrence of a tsunami in the last century was in Newfoundland in 1929, but evacuation plans should still be developed. It also notes evidence that a tsunami hit what would be the New York City area 2,300 years ago.
A 2013 study by a Boston College seismologist concluded that increased seismic activity in the North Atlantic could put New England in the path of a tsunami. A state mitigation plan published the same year recounted several earthquakes along the coast since 1668 that were reported to have impacted the waters of Massachusetts. It estimated nearly 1.6 million people lived in areas that could be exposed to a tsunami if it occurred.
Although the Virginia Department of Emergency Management has no tsunami-specific program, the city of Norfolk was the first on the east coast to earn “Tsunami Ready” status from the National Weather Service in 2006. To receive that designation, a city must undertake several activities related to preparation, response, and outreach.
Tsunami preparedness plans typically involve alert system, orders to evacuate inland or to high ground, and signs along the coast to direct people to safety. People are urged to recognize natural warning signs as well and be prepared. If they are unable to evacuate, it could be days or weeks before rescue crews are able to reach them.
Keeping warning systems and procedures up-to-date and well-practiced is the key for governments to avoiding false alarms and slip-ups like the recent mistaken missile alert in Hawaii.
“Any system that’s not tested isn’t dependable,” Holdeman said.
City and state governments on the west coast have worked to educate their communities on the possible danger of tsunamis and the steps that can be taken to protect against them.
“The coastal communities that are most at risk practice their tsunami warnings pretty frequently,” Alexander said.
In addition to drills in many areas, the National Tsunami Hazard Mitigation Program has designated “Tsunami Preparedness Week” campaigns in western states and ocean territories throughout the year, beginning in March.
“We can always use more funding, more people to help with all of these preparedness and resilience efforts, but it really comes down to what each individual is going to do,” said Ballmann, who helps run the annual Great ShakeOut earthquake drills.
It is helpful for citizens to know evacuation routes and prepare an emergency bag, but a coordinated and careful evacuation of millions of people from a crowded coastal city with giant waves approaching is a daunting task.
“A lot of people tend to think you can just jump in your car…. With a tsunami when you have tons of people trying to evacuate along the coast, it can be really difficult,” Ballmann said.
In the event of a nearby earthquake, a city may have less than a half hour before the resulting waves arrive. Adding to the complexity, an earthquake powerful enough to produce such a tsunami could also damage the infrastructure people need in order to evacuate.
Due to those circumstances, advance plans that can be executed quickly are essential for state and local governments.
“The biggest challenge is, of course, what do you do before it happens,” Ballmann said, “because everything you do before dictates how well you react during and how quick your recovery can be after.”
Alexander pointed to the visual spectacle of a massive wall of water crashing over the coast as another factor complicating evacuation efforts.
“People want to go see it,” he said. “They want to see the tsunami wave…that’s not what we want. We want people to get away from the coast.”