SAN FRANCISCO (AP) — More counties in California announced new COVID-19 restrictions on Saturday to prevent rising caseloads from spiraling into a hospital crisis. 

San Francisco is joining a statewide curfew and Silicon Valley is banning all high school, collegiate and professional sports and imposing a quarantine for those traveling into the region from more than 150 miles away. Santa Clara County has the highest case rate in the Bay Area, leading to the stricter rules, said Santa Clara County Health Officer Dr. Sara Cody.

“This pandemic is like a high-speed train, and our projections tell us that we are on target to derail by around the third week of December if we don’t apply the brakes right now with all our collective might,” she said.

The changes in Santa Clara County are less strict than a statewide lockdown issued in March by Gov. Gavin Newsom but still ratchet up measures that aim to slow the exploding number of people who have become infected with COVID-19 and those winding up in hospitals. It stops short of a full business shutdown that could cripple the holiday sale season by reducing the number of people allowed in stores to 10% capacity.

The order, which takes effect Monday and will last until at least Dec. 21, exempts church services and protests, which county health officials said are constitutionally protected.

Health officers in other Bay Area counties expressed support for Santa Clara county’s tighter rules because they anticipate other parts of the region may eventually reach the same critical caseload level. A month ago, there were 262 people hospitalized with COVID-19 in the Bay Area; as of yesterday, that number had nearly tripled to 759, they said in a statement.

The San Francisco 49ers and the San Jose Sharks hockey team may need to find a temporary new home after the county banned all contact sports from holding games and practices for the next three weeks. Stanford and San Jose State also have several sports in season.

Meanwhile, an alarming surge of newly reported coronavirus cases pushed San Francisco and San Mateo counties to the most restrictive purple tier in the state's pandemic blueprint for the economy, forcing most indoor activities to close by noon Sunday and placing the counties’ residents under curfew starting Monday night.

The new restrictions came a day after Los Angeles County imposed a lockdown calling for 10 million residents to stay home “as much as possible,” prohibiting them from gathering with people outside of their household for public or private occasions, except for faith-based services and protests.

Businesses already are operating under a recently-imposed nighttime curfew that covers much of the state, as are restaurants, which were recently barred from offering in-person dining. 

Public health officials have been urging people for weeks to avoid visiting family during the holiday season as COVID-19 cases spiral out of control in counties that include most of California’s population.

Authorities began to see caseloads spiking this fall and blamed it, in part, on people ignoring mask and distance precautions when gathering, especially to celebrate holidays or special events such as the World Series victory by the Dodgers and NBA championship win by the Lakers.

The state's top public health official has referred to “COVID fatigue" by people who are becoming lax about safety precautions after having been hit with sometimes confusing state and local health orders as the pandemic waxed and waned.

Meanwhile, health officials are bracing for a wave of cases in the next two or three weeks that could follow gatherings at Thanksgiving. Officials have estimated that 1 in 145 Los Angeles County residents is infected with COVID-19. About 12% of those infected could wind up in hospitals, authorities say.

“The big unknown here is what actions were people taking over this long holiday weekend,” county Public Health Director Barbara Ferrer said Saturday.

If people engaged in high-risk activities, she said, “we’re in for a very rough time because we will have a surge on top of a surge.”