West Marin did not panic during last Thursday’s tsunami alert, nor did it engage in a collective shrug. Instead, people along the coast—awaiting a potentially lethal wall of water—responded calmly and deliberately.

First came an earthquake alert at 10:44 a.m., reporting a 7.0-magnitude shaker off the coast of Eureka, some five hours north. Five minutes later, the National Weather Service issued an ominous warning for coastal communities stretching from Santa Cruz to Oregon: “A series of powerful waves and strong currents may impact coasts near you. You are in danger. Seek higher ground.”

Some residents felt the faint rumbling minutes before their phones started buzzing; others felt nothing at all. Nearly an hour of suspense ensued as the clock ticked toward 12:10, when waves were expected to strike the Point Reyes National Seashore and environs.

People along Tomales Bay wondered if they were safe or whether they should flee. Some did, some didn’t, but those in Stinson Beach and Bolinas, among the most vulnerable communities in West Marin, had no doubt about how to proceed.

As county emergency vehicles raced down Highway 1 to assist them, the local fire departments sprang into action. Tsunami sirens blared as teachers from the Bolinas-Stinson School hustled students to higher ground. Those in Stinson climbed the tsunami trail behind the school before being transferred to the emergency shelter at the Stinson Beach Community Center. School buses whisked Bolinas students atop the Big Mesa, where people evacuating from downtown had begun gathering at the fire station.

Some students shed tears, but for the most part, they remained calm. In Stinson, they ducked and covered in their classrooms when the earthquake alert went off and proceeded up the tsunami trail in orderly fashion, shepherded by teachers and staff who put their charges through drills once a month.

At the community center, teacher Omar Rifkin shared Abiyoyo and Anansi stories to keep the children calm and entertained. Among the assembled was 6-year-old Robin Waring, who was held rapt by the tales despite the potential for mayhem outside.

“He was excited to tell me about all the storytelling,” his mother, Vanessa Waring, later recounted. “The kids were just happy to get a story hour out of the whole thing.”

Ms. Waring, who works at the Bolinas Library, was among the first to arrive at the fire station; her 10-year-old son, Otis, arrived shortly afterwards with the students from the Bolinas campus.

“I was impressed with the way that the school handled it,” she said. “They were quick in their response and in making sure everyone was safe. I felt really cared for.”

Leo Kostelnik, the superintendent, said the practice drills paid off. “The students knew exactly what to do,” he said. “Of course, there were a few who were upset by the danger, but we were prepared to comfort them, and no one had a big episode that we weren’t able to address in real time.”

As the children evacuated, both villages shut down as firefighters and sheriff’s deputies fanned out downtown and warned people in low-lying areas to clear out. In Bolinas, they blocked the entrance to town to prevent anyone from potentially driving into a roaring flood. In Stinson, they went door to door in the Seadrift, Calle and Patio neighborhoods to make sure no one tested their luck and lingered.

Almost no one did.

“When the siren goes off, it definitely changes the atmosphere,” Stinson Beach Fire Chief Jesse Peri said. “It was quite an interesting scene for us, driving down the streets after just a couple minutes and seeing vehicles and people gone in areas that are normally populated.”

Further north, National Park Service staff evacuated visitors and staff from seashore visitor centers, parking areas and campgrounds, and posted warnings online.

As the clock ticked down, some more adventurous types gathered at the edge of the Bolinas bluff in hopes of taking in a spectacle. But by noon, the National Weather Service had canceled the warning, and people began returning to home, work and school.

When it was over, George Krakauer, the Bolinas fire chief, felt satisfied that things had gone as smoothly as possible.

“It was pretty incredible how fast people got the messaging and evacuated up to higher ground,” he said. “The downtown was almost completely vacated within minutes. It was well coordinated with the Office of Emergency Management, and it was a good drill.”

The epicenter of the quake was located off the coast about 40 miles southwest of Ferndale, according to the United States Geological Survey. It has been followed by dozens of aftershocks that continued this week, including a 4.2 temblor early Tuesday morning centered 46 miles southwest of Eureka.

After the tsunami warning was canceled last week, Willy Vogler, who runs Lawson’s Landing in Dillon Beach, heaved a sigh of relief. When the warnings went off, he quickly went online to see what was happening near the epicenter. But so many people had signed on to a website that tracks tide levels on the coast that the page crashed.

To play it safe, Mr. Vogler and the handful of visitors in town decided to head for higher ground. “I was kind of spooked,” he said. “You don’t have much time to make a decision. Run or stay? Leaving is probably the best bet.”