Alaska’s weekend tsunami warning led to evacuations and confusion

On Saturday night, Roger and Carol Christianson were settling into their RV parked at the end of the Homer Spit when their cellphones buzzed violently: A tsunami warning.

A 7.2 magnitude earthquake off the Alaska Peninsula had triggered the warning. Soon, the Michigan couple, touring Alaska with a group of other RVers, heard sirens sounding. That’s when they got nervous, said Christianson.

On the Spit, “you’re basically out there surrounded by water,” he said.

They quickly uncoupled a car they were towing and joined a long line of cars inching down the Homer Spit to higher ground.

Saturday night’s tsunami warning issued for the Gulf of Alaska coast from the Aleutian Islands to Cook Inlet was downgraded and later canceled, but not before many people evacuated low-lying areas, causing traffic jams and widespread confusion. Homer police dispatchers received “hundreds of phone calls an hour,” said the town’s longtime police chief Mark Robl. “It was chaos.”

People as far away as Anchorage — not at risk of a tsunami — also received the tsunami alerts on their phones. It wasn’t the first time. In 2020 a similar scenario led to Anchorage residents hundreds of miles away to “mistakenly” receive the warnings.

Emergency managers and tsunami scientists say they were simply following their own systems, which err on the side of caution and speed. But others worry that the confusion around whether the tsunami posed actual danger or not could ultimately erode the public’s trust of a crucial emergency warning system.

“This is our concern: We’re going to have a cry-wolf situation where people aren’t going to respond to the warning anymore and they just won’t evacuate,” said Robl, Homer’s police chief.

[Earlier coverage: Why cellphones in Anchorage keep getting emergency tsunami alerts when there’s no danger after faraway quakes]

It’s important to understand exactly how the system works, said James Gridley, the director of the Tsunami Warning Center in Palmer. A large enough earthquake can trigger a release of energy that can lead to a destructive tsunami wave. When sensitive instruments pick up such an event, an automated alert goes out — there’s no time to verify whether a destructive wave is actually forming, Gridley said.

“We issue a warning right away — because we need to get anybody in the immediate area out of danger right away,” he said.

After that, on-duty scientists with the Tsunami Warning Center review data from a network of buoys and other instruments to determine whether a wave is forming, and what size it is, Gridley said. Warnings are revised or canceled. That part of the response can take about an hour, he said.

Meanwhile, an alert from the Tsunami Warning Center can trigger an emergency response. Federal, state and local emergency management entities follow their own procedures for what happens when an initial tsunami warning alert is received, usually through a notification sent by the National Weather Service. Those responses — which could include sirens warning residents to evacuate or other actions — can vary, said Gridley. They are not controlled by the Tsunami Warning Center, which supplies information but does not manage the response.

On Saturday night, the earthquake was large enough to trigger a tsunami warning and two modes of informing residents: The Kenai Peninsula Borough sounded its network of tsunami warning sirens, said emergency manager Brenda Ahlberg. And lots of people throughout the region got cell phone notifications.

The Wireless Emergency Alerts are the reason people as far away from Anchorage, which was never in danger of a tsunami, felt their phones buzz and saw a dire-sounding warning on the screen. The alerts blast out to anyone in the geographic area of certain cell phone towers in a zone that can be widely defined.

The wireless emergency alerts are a bit of a blunt instrument, said Gridley. They are not “geo-fenced” to target only people in potential inundation zones, he said. It’s good that so many people can be reached so quickly, but the broad zones can cause people who don’t need the alerts to get them.

“We’re aware of this,” he said. “We’re working with the (National Weather Service) to try to hone this down to a better system but that takes some time.”

[From 2020: Tsunami alerts were mistakenly sent to Anchorage after 7.8 earthquake off Alaska Peninsula, officials say]

The Kenai Peninsula Borough only has the capacity to deploy sirens systemwide — not just in specific communities, said borough emergency manager Brenda Ahlberg.

“Right now, sirens go off everywhere,” Ahlberg said.

The initial siren sounding is automatic when triggered by a tsunami warning, Ahlberg said. From there, the sirens are supposed to sound again every 10 minutes until an all-clear message is issued by the Tsunami Warning Center. That’s what happened on Saturday night, Ahlberg said.

On Saturday, Ahlberg said it wasn’t initially clear that Cook Inlet communities like Nanwalek and Port Graham, were not at risk.

“While Homer may have felt confident that the sirens need to be ignored, I have coastal communities around the other side of that bay that potentially were in harm’s way,” Ahlberg said. “Until I have clear (indications) that we are not in harm’s way then I will follow my standard operating procedure.”

Starting later this month, the borough is installing a new tsunami siren system that will allow for precise, community-by-community warnings. Ahlberg described the change in technology as “from rabbit ears TV to Netflix.”

Ahlberg said emergency managers will soon meet to debrief about what happened on Saturday. But as long as tsunamis remain a genuine threat, she doesn’t think the evacuations were in vain.

“Is it unfortunate that they have been false alarms, or is it fortunate that we have been able to deploy the system, get people out of harm’s way, and then realize it wasn’t necessary?” she asked.

The Christiansons, the RV couple from Michigan, took the experience in stride. They got off the Homer Spit and sought shelter in a school parking lot.

It was different than the tornado warnings common in the Midwest, Carol Christianson said: There, you can expect nonstop live TV coverage of severe weather. In the middle of Saturday night, they weren’t exactly sure where to turn for information. But ultimately, they returned to the Homer Spit RV site and went to bed, they said. It wasn’t easy to sleep.