A lingering heat wave lured people to California beaches, rivers and trails again Sunday, prompting warnings from officials that defiance of stay-at-home orders could reverse progress and bring the coronavirus surging back.

Tens of thousands of people packed the sand at Newport Beach in Orange County, where residents compared weekend crowds to July 4 and lifeguards reminded people to stay apart if they were in groups of six or more.

City officials announced Sunday that the City Council will hold a special meeting Tuesday to discuss issues including temporary weekend beach closures.

Thousands of beachgoers enjoy a sunny day at Huntington Beach despite the state-mandated stay-at-home order on April 25, 2020. (Allen J. Schaben/Los Angeles Times)

Neighboring Huntington Beach also saw big gatherings, despite the closure of beach parking lots and metered parking restricted along Pacific Coast Highway.

Robin Ford, a resident of the coastal city known for its pier, surveyed the crush of visitors with concern.

“Our beach is so big, that I feel people can distance themselves — but it’s a lot more crowded today,” Ford told the Orange County Register on Saturday. “Unless all these people are in one household, it does look like they are not social distancing. They could be spread out more.”

Weekend temperatures reached the 80s and 90s in much of the state. While most recreation remains shuttered under various orders, officials were wary that those still open could draw people who will ignore rules to stay separated and seek sun and air after being mainly confined indoors for more than a month.

Los Angeles city and county beaches, trails and playgrounds were closed, and officers on horseback were patrolling those areas to enforce social distancing rules.

“We won’t let one weekend undo a month of progress. While the sunshine is tempting, we’re staying home to save lives,” Garcetti tweeted Sunday. “The places we love — our beaches, hiking trails — will still be there when this is over. And by staying home, we’re making sure our loved ones will be too.”

To the north, police in Pacific Grove said they had to close the picturesque Lovers Point Park and Beach at the southern end of Monterey Bay because of a lack of social distancing.

Most people who flocked to the East Bay Regional Park District’s nearly 125,000 acres (195 square miles) of park land east of San Francisco followed social distancing guidelines, but some people ignored the signs and gathered in large groups, the district’s general manager told the San Francisco Chronicle.

The biggest violators refused to leave closed picnic areas when asked, Robert Doyle said.

Police closed parking lots in Sausalito to deter people who flocked to the popular seaside town across the Golden Gate Bridge from San Francisco. Police said the lots will be closed on weekends and holidays until further notice because of “widespread disregard for non-essential travel restrictions.”

In Sacramento, boats crowded the water at Discovery Park and many families set up blankets and chairs by the riverside.

“We want to continue to remind the community that yes, the weather is nice, but COVID-19 is still around, and we’ve been making some great progress,” Sacramento County Sheriff’s Deputy Zaheem Buksh told KCRA-TV. “So let’s continue to make that progress by practicing social distancing.”

California has had more than 42,500 coronavirus cases and nearly 1,700 deaths, more than half of them in the Los Angeles area, according to data compiled by Johns Hopkins University. However, the number of infections is thought to be far higher because many people have not been tested, and studies suggest people can be infected with the virus without feeling sick.

Last week, health officials announced a Santa Clara County woman died in early February from COVID-19 — weeks before the first previously known U.S. death from the virus. An autopsy released by the county Saturday concluded she suffered a massive heart attack caused by coronavirus infection, which also spread to her trachea, lungs and intestines.

San Francisco Mayor London Breed said more than a month into the crisis the Bay Area still faces shortages of personal protective equipment and testing kits. It’s causing challenges that will exacerbate if the virus surges back, she said.

“We have known that this crisis was coming to our country for a long time now, and the fact is that as of April, we’re still having the same conversations about the challenges,” Breed said Sunday on CBS News’ “Face the Nation.” “I know that most cities are seeing the same data I’m seeing that if we do absolutely nothing, it gets worse.”

For most people, the virus causes mild or moderate symptoms, such as fever and cough that clear up in two to three weeks. For some, especially older adults and people with existing health problems, it can cause more severe illness and death.

Cases continue to grow in California but at a manageable pace that hasn’t overwhelmed hospitals, health authorities have said. State and local stay-at-home orders have been cited as successfully slowing the rise in coronavirus hospitalizations and deaths. Recent polls show Californians overwhelmingly support them.

There have been small protests by people who want to reopen the state, contending their liberty and livelihoods are at stake. Three people were arrested at a rally Saturday in Encinitas, just north of San Diego, and cited for violating health orders, Sheriff’s Lt. Ricardo Lopez said.

A special City Council meeting has been scheduled for 3 p.m. Tuesday, April 28 with 3 agenda items related to coronavirus response and recovery, including developing a committee to guide business reopening and temporary weekend beach closures. For more: https://t.co/zxsu661QaH. — City of Newport Beach (@newportbeachgov) April 26, 2020