CNN  — 

Millions of Californians will likely find themselves under a regional stay-at-home order once again under new restrictions announced Thursday by Gov. Gavin Newsom.

The new order will take hold in regions where hospitals are feeling the squeeze on capacity to treat the incoming surge of Covid-19 patients. A strict stay-at home order will go into effect 48 hours after hospital intensive care unit capacity drops below 15% in one of five regions the state is divided into: Northern California, Bay Area, Greater Sacramento, San Joaquin Valley and Southern California.

“We are at a tipping point in our fight against the virus and we need to take decisive action now to prevent California’s hospital system from being overwhelmed in the coming weeks,” Newsom said.

The order comes as the state experiences a record surge of new cases and hospitalizations that are projected to overwhelm hospitals by Christmas. The state added 18,591 more cases Thursday, bringing the total to 1.2 million.

Hospitals are treating 2,066 Covid-19 patients, according to data from the state health department, the highest number yet in the pandemic.

None of the regions currently meet the threshold but state officials project four of the regions will drop below 15% ICU capacity in early December, with the Bay Area to follow in mid-to-late December, Newsom said. The five regions include 99% of the state’s 39 million residents.

“We need to do everything we can to stem the tide” until coronavirus vaccines are ready for the public, the governor said.

Once the new order is triggered in a region, it would remain in effect for three weeks, but could stretch on much longer.

Schools that are already open for in-person learning can remain open along with critical infrastructure businesses. Retail business may stay open but at 20% capacity, and restaurants are limited to take out and delivery only.

When a region falls under 15% ICU threshold, business that must close include bars, wineries, personal services like hair salons and barber shops, museums, movie theaters, playgrounds, amusement parks and indoor recreation facilities.

Travel is prohibited except as necessary for permitted activities. Newsom said he expects this is the last time that a stay-at-home order will be needed during the pandemic.

“We do not anticipate having to do this once again,” Newsom said. “There is light at the end of the tunnel. We are few months away from truly seeing real progress with the vaccine. We have distribution, we have accessibility, we have availability.”

At the end of those three weeks, health officials will look at transmission rates and make ICU projections based on that data, according to state Health and Human Services Director Dr. Mark Ghaly. They will outline what’s expected to come using the average of 12% of patients needing hospitalization.

If a county’s transmission rate lends itself to projections of ICU beds at a higher capacity, the stay-at-home order will be lifted and the county will return to the state’s four-tier system of reopening.

Los Angeles mayor tells residents ‘cancel everything’

The mayor of Los Angeles said the city will run out of hospital beds by Christmas if the coronavirus spreads at its current rate as he urged residents to remain home to help stop the spread of the virus.

Residents should stay home as much as possible as the city faces stark choices between “health and sickness, care and apathy, life and death,” said Mayor Eric Garcetti during a Wednesday news conference.

“It’s time to hunker down. It’s time to cancel everything. If it isn’t essential, don’t do it,” Garcetti said. “Don’t meet up with others outside your household, don’t host that gathering, don’t attend a gathering.”

The number of daily coronavirus infections in Los Angeles has tripled since early November. Hospitalizations have more than tripled and are at a new peak, Garcetti said.

“The public health condition of our city is as dire as it was in March in the earliest days of this pandemic,” he said.

Los Angeles is in line with the rest of the country as Covid-19 hospitalizations have soared. The 100,226 Covid-19 patients in US hospitals on Wednesday is the highest reported during the pandemic, according to the Covid Tracking Project.

Health care officials across the country say their staff and facilities are struggling to support burgeoning numbers of patients.

Los Angeles County on Tuesday reported its highest number of hospitalizations and new coronavirus cases since the start of the pandemic. Average daily cases have increased by 225% since early November, according to the Los Angeles County Department of Public Health.

“Every resident and every business needs to take immediate action if we are to dampen this alarming surge. We are in the middle of an accelerating surge in a pandemic of huge magnitude,” said Barbara Ferrer, director of the Los Angeles County Department of Public Health, in a statement. “This is not the time to skirt or debate the safety measures that protect us because we need every single person to use every tool available to stop the surge and save lives.”

The county, the most populated in the nation with 10.5 million residents, is now under an order that bans all public and private gatherings with anyone outside a single household. The ban was issued last week by the county public health office and ends December 20.

All county residents are asked to stay home as much as possible and wear face masks when outside, even when exercising. The order reduces the maximum occupancy for essential businesses to 35%, and for nonessential businesses, personal care services and libraries to 20%.

The directive follows a ban on in-person dining in Los Angeles County and a statewide curfew prohibiting nonessential activity outside the home from 10 p.m. to 5 a.m. for most of the state’s 39 million residents.

Patients needing intensive care will surpass capacity, according to state projections. Statewide, ICU capacity is projected to be 112% by mid-December while Northern California is projected to see 134% more ICU patients than beds by early December.

CNN’s Jon Passantino and Cheri Mossburg contributed to this report.