After a relative New Year’s lull, California on Monday reported its highest number ever of new coronavirus cases in a single day, logging more than 74,000, according to a Times tally of local health jurisdictions.

That is 11% higher than the previous record, when 66,726 cases were registered Dec. 28. The tally is likely affected by both a backlog of cases from counties that did not report over the New Year’s Day weekend and the closure of some testing sites over the holiday.

The state is now averaging about 37,000 new cases a day over the last week, down from a high of about 45,000 in mid-December. But the situation is still far worse than in the beginning of December, when 14,000 cases a day were recorded.

California also posted its sixth-highest daily tally of COVID-19 deaths Monday: 379. That increased the average number of COVID-19 deaths over the last week to 353 a day, the highest number yet.

In Los Angeles County on Monday, an additional 79 coronavirus-related deaths and 10,851 infections were reported. Over the last week, the county is averaging 184 COVID-19 deaths a day — the equivalent of one every eight minutes — and about 13,500 cases a day, a count expected to grow with the reopening of testing sites.

The immense infection count is “a human disaster, and one that was avoidable,” County Supervisor Hilda Solis said.

“The situation is already beyond our imagination,” she said during a briefing Monday. “But it could become beyond comprehension if the health restrictions in place are not fully obeyed.”

Even when figures are adjusted to account for the state’s population, California’s coronavirus outbreak ranks among the worst in the country.

Over the past week, California has averaged roughly 96 new daily cases per 100,000 residents — tied with Rhode Island for the second-highest rate among all states, behind only Arizona’s 112, according to data from the Centers for Disease Control and Prevention.

The nationwide daily average for new cases over that same period has been about 64.

In the face of an already overwhelming surge, California is also now faced with another potential threat: the presence of a new coronavirus variant first identified in the United Kingdom that some scientists believe is even more contagious.

Though it’s unclear how prevalent the variant is statewide, San Diego County health officials reported 24 additional confirmed cases Tuesday, along with four more probable cases. That raises the county’s total number of known or suspected variant infections to 32.

The two dozen newly infected patients “are believed to have no travel history and to have come from 19 different households, but the investigation and contact tracing are ongoing,” according to a statement by county officials. Those infected are widely dispersed geographically and range in age from 10 to in their 70s.

“The fact that these cases have been identified in multiple parts of the region shows that this strain of the virus could be rapidly spreading,” Dr. Wilma Wooten, the county’s public health officer, said in the statement. “People should be extra cautious to prevent getting and spreading COVID-19, especially this variant, which research has shown is more contagious.”

The variant has also been identified in two people of the same household in Big Bear in San Bernardino County.

Experts say there’s no evidence that the variant — known as B.1.1.7 — is deadlier, causes more severe illness or renders existing vaccines ineffective.

But any heightened risk of infection is unwelcome news, particularly in areas already reeling from sky-high levels of coronavirus transmission.

Though L.A. County officials have yet to document the variant’s presence there, “having a virus that is able to infect more people more quickly than what we’re seeing today” is a “frightening thought,” county Public Health Director Barbara Ferrer said Tuesday.

While many of those infected may experience only mild symptoms — or none at all — California health officials have warned that a sizable slice, about 12%, will fall ill enough to require hospitalization within a few weeks after they are exposed.

A significant and sustained wave of new infections, then, will invariably slam hospitals with additional patients.

“This week is critical in terms of a bigger understanding of where we are and if we’re going to hit that surge on top of a surge, on top of yet another surge,” Gov. Gavin Newsom said.

Though the figures dipped somewhat around New Year’s Eve and New Year’s Day, the number of coronavirus-positive patients hospitalized statewide rose to 21,597 Monday, a new record. Of those patients, 4,634 were in intensive care units.

The story is much the same on the local level, as California’s most-populated counties continue to see record or near-record levels of hospitalizations.

Conditions in ICUs, which require specialized staff and equipment to care for the sickest patients, are of particular concern. The availability of intensive care beds in Southern California and the San Joaquin Valley has stood at 0% for weeks — a distressing metric that doesn’t mean that no beds are available at all, because the state uses a weighted formula to ensure that some remain open for non-COVID patients, but does indicate that hospital capacity is stretched to the limit.

Health officials in San Joaquin County reported Monday that the need for intensive care had reached an all-time high, with adult ICUs at 175% above their licensed bed capacity.

“The impact of COVID-19 on the members of our community and our healthcare system is glaring,” Dan Burch, the county’s EMS administrator, said in a statement.

In the Bay Area and Greater Sacramento, where ICU availability stood at 5.9% and 11.7%, respectively, as of Tuesday, the situation is less dire, but still concerning.

All four of the state-defined regions where ICU availability is below 15% are under stay-at-home orders, which include a host of restrictions on businesses and activities aimed at stymying coronavirus transmission.

Those orders will remain in place until a region’s available ICU capacity, forecast four weeks out, is 15% or higher.

In L.A. County, the number of hospitalized COVID-19 patients rose to 8,023 on Monday — 125 more than the previous day. Of them, 1,642 were in the ICU, also a record.

“It is getting harder and harder for healthcare workers to care for those coming to the hospital with gunshot wounds, heart attacks, strokes and injuries from car accidents,” Solis said. “Hospitals are declaring internal disasters and having to open church gyms to serve as hospital units. Our healthcare workers are physically and mentally exhausted and sick.”

The number of COVID-19 patients in ICU wards has quadrupled since late November.

“Given the current state of the pandemic in Los Angeles County, the worst is almost certainly still ahead of us,” Dr. Christina Ghaly, the L.A. County director of health services, warned. “As of today, hospitals continue to be significantly strained. All hospitals are being inundated with COVID patients.”

She said overcrowded hospitals have been forced to leave patients in hallways or keep them waiting in ambulances.

“The demand for oxygen is so great that some hospitals are having trouble maintaining an adequate degree of air pressure to keep a high-flow rate of oxygen pumping into lungs of COVID-19 patients that have been inflamed,” Ghaly said.

As conditions continue to deteriorate, officials have noted with alarm that many Californians disregarded their pleas to stay home for the holidays — while some anti-maskers have joined in protests against the health orders that are in place.

“We are in the midst of an unprecedented and dangerous surge,” Solis said. “Despite what protesters claim, this is not a hoax.”

Ghaly reminded residents of the role they play in battling the worst public healthcare crisis of the last 100 years, and that wearing or not wearing a mask in public doesn’t just affect the person making that choice.

“It’s not about you; it’s about the other people around you,” she said. “And in this time of mass crisis, we need to think of our neighbors. Please show others the basic common courtesy and take the lifesaving action of wearing a mask when you’re around others.”

While officials say it’s understandable that Angelenos are frustrated with the continued restrictions and tired of living with the looming threat of the pandemic, they point out hope is on the horizon, given the recent arrival of COVID-19 vaccines.

Since mid-December, L.A. County has received about 357,500 doses, including 189,995 doses of the Pfizer vaccine that has primarily been used to inoculate healthcare workers at 83 acute-care hospitals, Ferrer said during Tuesday’s Board of Supervisors meeting.

As of Sunday, 60% of the Pfizer doses had been administered to frontline healthcare workers at hospitals, Ferrer said.

The county has received about 170,000 doses of the Moderna vaccine, which will be given to residents and staff at skilled nursing facilities, as well as emergency medical technicians and paramedics, among others.

Ferrer said it had been a challenge to vaccinate healthcare workers because many have been busy contending with the COVID-19 surge at their hospitals. One vaccine site, she said, also had to turn away a crowd of more than 150 non-healthcare workers who showed up Monday.

“I think it’s a very positive sign that lots of people are ready to be vaccinated,” but the public must be patient as the county works through vaccinating healthcare and essential workers and other priority populations, Ferrer said.

The county this week will receive a “much smaller” shipment of vaccine doses than the federal government had originally indicated, which will only be enough to allot to acute-care hospitals for the second doses of vaccine for their workers, Ferrer said. That, too, could slow progress.

“I think we were all expecting a lot more vaccine would come to the state, and we would get our fair share of that,” she said.

It’s unclear at this point whether that’s the result of an issue in production, distribution or something else, Ferrer added.

“If we get enough doses, we hope we would complete vaccinating the healthcare workers and those in long-term care facilities [by the] end of January, beginning of February,” she said. “The ‘if’ there is really dependent on getting enough vaccine.”

Times staff writers Jaclyn Cosgrove and Andrea Roberson contributed to this report.