SEATTLE — One unseasonably warm day in late March, dozens of people streamed into a popular park in Seattle's Capitol Hill neighborhood to stroll the pathways, walk their dogs and play soccer. Suddenly, a police cruiser appeared and drove through the park, lights flashing.

"Your current conduct is placing yourself and your fellow Seattleites in danger," an officer announced over the loudspeaker, "and I'm asking you to leave this area."

The police action in Cal Anderson Park on March 21 was part of a swift and unusually bold response to the novel coronavirus outbreak that appears to be helping Seattle and surrounding King County avoid the worst predictions about the crisis. By implementing widespread testing, quarantining the homeless and waging an aggressive campaign to enforce stay-at-home orders — including by using highway toll records, traffic cameras and Facebook data — the region is bringing the virus under control.

Though King County was the site of the nation's first deadly outbreak, the latest data shows the rate of infection is slowing, hospitalizations are dropping and the numbers of deaths and new cases are expected to peak this week. Despite a feud with federal officials that cost the region thousands of promised test kits, officials here say they are cautiously optimistic.

The approach has gained attention, and praise, across the country, largely because it stands apart from other states that waited to implement social distancing policies until after outbreaks became overwhelming. As beaches remained open and spring break parties raged in Florida, Mardi Gras celebrants hit the streets in New Orleans, the mayor of New York went to the gym, and several governors flaunted dinners out on social media, Seattle tried to shut itself down.

"One thing that stands out in terms of blunting the velocity of the virus is how quickly in the Seattle area . . . they were able to institute social distancing," said Lee Riley, a professor at the University of California at Berkeley and chair of the university's Division of Infectious Diseases and Vaccinology. "That's probably the big factor in all of this. In Hong Kong, Singapore, Taipei, Korea and other places where they saw early success, you saw the same thing."

Last week, Deborah Birx, the White House coronavirus task force response coordinator, credited Washington state and California for their early reactions to the crisis.

"They brought together their communities and their health providers and they put in strong mitigation methods and testing," Birx said, adding that Washington "really talked to their communities and decided to mitigate before they started seeing this number of cases."

"Before there were any cases in Seattle, we were taking action," Seattle Mayor Jenny Durkan said. "If you're wondering if you should act today, it probably means you should have acted last week."

King County had some built-in advantages. Wealthy and highly educated, the county is home to dozens of big tech companies that were able and willing to shift to telecommuting. And the first cluster of U.S. deaths at the Life Care assisted-living center in Kirkland created an immediate sense of crisis.

Officials here say they had to act quickly, pursuing policies that were unpopular before the public fully understood the danger — such as ordering police to kick people out of a park on a sunny afternoon.

"Throughout this, I have been admonishing people, my staff, anyone who will listen: Whatever the thing is that we're not comfortable with today but we're going to be comfortable with two or three weeks from now, we should do that now," King County Executive James "Dow" Constantine said. "Everyone is pushing their way through this and untangling their expectations of what life in America is supposed to look like."

Reality shift

America's first-known covid-19 case emerged just outside Seattle, in Snohomish, on Jan. 21.

A few days later, Durkan convened a regularly scheduled "table top" exercise — in which leaders gather in a conference room and simulate potential disasters — and they decided to go through the paces of how to respond to a pandemic that hadn't yet been declared a pandemic.

"When it came time to turn the dials, we had playbooks ready to go," Durkan said.

By late February, the region had become the nation’s singular hot spot, and the first-known virus-related death came on Feb. 28. Life Care Center of Kirkland was the epicenter, with 129 residents, staff members and visitors falling ill and 40 people dying.

Washington Gov. Jay Inslee (D) issued a state of emergency on Feb. 29, but messaging created unique challenges in the early days, county officials said. People knew the virus was bad, but there was not yet a sense of crisis.

“We had all these pro sports events on the calendar, including Opening Day for Major League Baseball,” Constantine said. “On February 29th, it was still unthinkable that a few weeks later we wouldn’t have Opening Day. It’s hard for people to shift their reality that much that quickly. So there was a series of leaps where we’re telling people reality has changed.”

Hours after the first Life Care deaths were publicly revealed, King County officials convened a conference call with executives for 19 of the region’s foremost tech companies and urged them to allow their employees to work remotely.

Microsoft was among the companies that swiftly sent workers home.

“I think what we learned from China is how quickly you have to shift your mind-set,” Microsoft President Brad Smith said. “The first principle that guided our decision-making was a conviction that we needed to listen to people with public health expertise.”

John Wiesman, the state’s secretary of health, said the Puget Sound region’s ability to work at home had a huge impact, preventing potential spread at major companies and keeping many people from interacting. Three days later, Seattle officials asked all residents with nonessential jobs to work from home and recommended that anyone over 60 stay home entirely if possible.

The people of King County were particularly well-positioned to respond. People here are younger, better-educated and far wealthier than the national average, with a median household income of $95,000, more than 50 percent above the U.S. median. More than half of King County's adults have a college degree, compared with a third of adults nationally, and 16 percent of the workforce is employed in information technology.

And the county had access to tracking data that helped determine the effectiveness of each new measure. Location data shared by Facebook’s Data for Good project showed traffic into Seattle dropped 90 percent in March, while the daytime population of residential areas in the region increased 27 percent — a sign that stay-at-home policies were working.

On March 13, Inslee ordered a ban on gatherings of 250 or more people in the Seattle metro region — one of the first of its kind in the country — beginning an escalating series of orders to limit movement and exposure. Inslee issued a statewide stay-at-home order on March 23, also among the first in the nation.

“As Americans, we were raised with an internalized sense of civil liberties, the right to assemble,” Constantine said. “It’s very much against the grain to tell people they can’t group.”

Mayors around King County took on the task of discouraging gatherings. In the town of Redmond, Mayor Angela Birney had all playground equipment roped off in caution tape. She and her staff wrote pen-and-paper letters and phoned the elderly to explain why senior programs had been suspended.

She altered police patrol routes to focus on likely gathering places, and on one particularly nice day, she urged officers to politely disperse people outside an ice cream shop.

“We’re not making arrests, of course,” she said.

Testing

If social distancing was King County's first step, getting the virus under control required a vital second step: County health officials needed to be able to test people for the infection.

With a multiple-day wait for test results, doctors and nurses were using large amounts of personal protective equipment — such as masks, gloves, smocks and face shields — as they were forced to assume that each patient exhibiting symptoms carried the virus.

As supplies ran low, Overlake Hospital in Bellevue sent dozens of requests to the federal government for ventilators, gowns, face shields and masks, but hospital officials said they got just a few shipments. So they got creative, ordering several dozen face shields manufactured for paintball shooting competitions.

“It turns out the paintball industry has some wonderful equipment. Whole face shields. And unlike ours, they’re anti-fog!” chief medical officer David Knoepfler said.

Once it became clear in early March that the testing turnaround from the federal Centers for Disease Control and Prevention — three to five days at the time — was not likely to improve, King County’s health department played point in the effort to turn around tests rapidly. The county funneled kits to a state facility in Shoreline and, later, the University of Washington.

“CDC fumbled that ball pretty quickly,” Knoepfler said. “King County Public Health took that on themselves and tried to increase capacity as quickly as they could.”

Another incentive to do it themselves: The Federal Emergency Management Agency required photo identification, health insurance information, phone numbers, email addresses and home addresses for every patient tested, according to a letter the agency sent to the county that was obtained by The Washington Post. The agency also ordered county officials to ship the kits to labs with CDC contracts on the East Coast, which would yield results in as long as a week.

Federal officials did not provide a rationale for gathering personal information or their insistence on cross-country shipping, county officials said. But the demands set off alarm bells in King County, a “sanctuary” jurisdiction that has come under fire from the Trump administration for its immigration policies.

“Obviously that raises a whole different set of suspicions,” Constantine said. “A pandemic is the perfect example of why we don’t want people hiding in the shadows and being afraid to get tested. You can be infected by a citizen or noncitizen equally. Your immigration status is not relevant. And having the threat of deportation hanging over you only makes it more likely you will avoid testing and appropriate treatment.”

So King County simply refused to comply and began processing all its tests locally. The decision seemed to provoke the Trump administration.

Patty Hayes, director of public health for Seattle and King County, said the federal promises and deliveries shifted: “First they were bringing a tent and all the staff and it was going to be 10,000 tests. Then no staff and 8,000 tests. It only ended up being 4,000. . . . It was a whole series of stuff where we said, ‘This just isn’t workable.’ ”

A FEMA spokesperson, Elizabeth Litzow, said the agency never committed to sending 10,000 tests to King County but confirmed that the agency was piqued by the decision to test kits locally, which was not “according to the plan.” When it became clear that King County would not adhere to FEMA’s “stipulations,” the spokesperson said, the agency ended its relationship with the county.

Each testing site “had to adhere to the entirety” of the federal directions or the government “could not support that location,” Litzow said.

Distance

King County has even taken the rare step of working to fully quarantine potentially at-risk populations.

In late March, a 62-year-old man tested positive for the coronavirus at an inpatient center for drug and alcohol rehabilitation that serves homeless men in Burien. Seattle’s Union Gospel Mission had been preparing for this moment at the urging of county officials, and it locked down all five of its Seattle-area properties.

The rationale: Employees who serve multiple facilities, in addition to men and women who had recently moved from one site to another, had the potential to contaminate several populations. The mission spent the next day — March 26 — lining up staff willing to shut in for a week with 300 homeless guests who could have been exposed to the virus. Guests could choose to leave the facility, but they were not allowed to return. Mission leaders said that if one person was infected, they had to assume there might be others.

“Those decisions can’t be drawn out,” said Scott Chin, the mission’s president. “Maybe some would criticize us for being this vigilant, but to be honest, I’d rather be criticized for that than the opposite.”

And then came testing, a small coup for the county. Officials set up a tent in Burien and started testing everyone, including 50 patients and nine staff members, a rare chance to play offense. During the downswing in hospital cases, they have been aiming to root out mini-outbreaks at their sources and contact trace the virus’s movement. They also have been working to provide shelter to homeless people that allows for social distancing, including renting local hotels.

“Knowing how this virus spreads, you have to determine who are your most vulnerable populations and have plans for them,” Durkan said. “So we worked with King County very closely to try to stand up additional shelter capacity so people experiencing homelessness could have distance between them.”

And county officials said they are exploring whether they would allow those quarantining in county facilities to leave at will, regardless of whether their symptoms have subsided. Constantine said such patients are likely to be followed out of the facility by security and questioned by law enforcement, a measure that would have been unfathomable a month ago.

Durkan implored cities nationwide to take the coronavirus seriously because places that contend they’re not at risk could realize they’re in the thick of the crisis after it is already too late. And without enough testing, she said, it’s impossible to know how to handle the virus.

“We still do not have adequate testing to do the kind of intervention and mitigation that we know we have to do,” Durkan said. “In hindsight, I would say that if I was in a city just seeing my first cases, I would assume that I had at least 10 times the cases that I have positive tests for, because testing capacity is so limited everywhere in the country. And act accordingly.”

Joel Achenbach, Desmond Butler and Chris Mooney in Washington contributed to this report.