The autumn COVID-19 surge has now spread not only through major urban areas like Los Angeles but across California and even to the far northern rural reaches of the state, a troubling sign as the state faces its greatest challenge from the pandemic yet.

A Los Angeles Times data analysis found that most California counties are now suffering their worst coronavirus daily case rates of the entire COVID-19 pandemic, surpassing even the summer surge that had forced officials to roll back the state’s first reopening in the late spring.

The data suggest California will face new problems in December if the unprecedented rise in cases continues. In earlier phases of the pandemic, different parts of California could help harder-hit areas, like San Diego County and San Francisco taking in patients from Imperial County. But that could be difficult in this wave, with the pandemic worsening in most places across California simultaneously.

“We can’t depend on our counties next to us because they are under the same stress and strain,” said Dr. Marty Fenstersheib, the Santa Clara County COVID-19 testing officer. “They can’t provide us with beds in their counties. So we are on our own. And our hospitals are hurting at this point.”

The Times analysis also demonstrates how the coronavirus has managed to break free from densely packed neighborhoods in urban areas and farming communities in agricultural valleys, where the virus infected essential workers — many of them Latino — who had no choice but leave home to work.

Now, infections are spreading faster in other communities. In Marin County, health officer Dr. Matt Willis said the pandemic has moved from just hitting predominantly Latino communities. Now, in just the last month, “the majority of cases are among our white residents,” Willis said.

“We’re finding a greater proportion of those cases among people who are gathering indoors, and might have a more reasonable option to avoid those exposures, because they’re based on personal choices,” Willis told the Board of Supervisors. “It’s most discouraging that that’s what is driving it — but also encouraging because we think those are behaviors that people have more control over, because it’s not a matter of economic necessity.”

In just the last week, record average daily coronavirus case rates have hit L.A. and other hot spots like San Bernardino and San Diego counties, the Times’ analysis found, which have already received much attention in recent weeks as hospitals have begun to fill and where, in some cases, the daily death toll has risen. The crisis has only become exponentially worse in recent weeks.

Many other counties are also seeing record highs in their average daily case rate observed just the last week, according to the Times analysis, including Ventura, San Luis Obispo, Santa Clara, Sacramento, San Mateo, Solano, and Santa Cruz. Counties across Northern California have also posted record highs in recent days, such as Napa County; Yolo County, home of the University of California, Davis; Nevada, Placer and El Dorado counties, which sprawl from the state capital’s suburbs to Lake Tahoe; and sparsely populated Mariposa County, home to Yosemite Valley.

In all, more than 23 million Californians, living in 31 counties, are currently in what’s shaping up to be the worst wave of the pandemic, the Times analysis found.

Across California, the seven-day average of daily coronavirus cases have more than quadrupled since mid-October, from less than 3,000 a day to nearly 14,000 a day as of Wednesday. In just two weeks, average daily deaths have doubled: every day, 74 Californian COVID-19 deaths are reported on average as of Wednesday, up from an average of 38 a day.