COVID-19 roared back in Minnesota in October, breaking records for case counts and leading to more reported deaths than in any month since May.

Doctors fear the forbidding trend won't slow in November, with more deaths and serious illness likely along with mounting pressure on hospitals.

Saturday's numbers continued to be grim.

COVID-19 has claimed 20 more lives in Minnesota, state health officials announced, bringing the number of deaths reported in October to 423 — nearly double September's total and the highest one-month tally since May. The number of positive cases reported Saturday topped the 3,000 mark for the second day in a row and for only the second time since the start of the pandemic, reflecting a surge that's approaching what is now being seen in Wisconsin, Iowa and the Dakotas.

"The good news right now is that we tend to see fewer people dying per case discovered than we did, for example, in March and April and May," said Dr. Jonathan Temte, associate dean for public health and community engagement at the University of Wisconsin School of Medicine and Public Health. "However, there's such a huge caseload ... that this is going to translate into a significant rise in my state and in your state, of hospitalizations and of deaths."

For the week ending Saturday, Minnesota averaged more than 2,300 new cases per day, a jump of more than 700 cases per day from a week earlier.

The increase has pushed Minnesota's rank among all states in terms of population-adjusted new case growth to No. 11, according to data posted Saturday on a tracking website at Brown University. North Dakota, South Dakota and Wisconsin held the top three spots in the nation, respectively, with rates that remain significantly higher than in Minnesota.

Last week, Mayo Clinic announced it would start delaying some nonemergency procedures at its hospital in Eau Claire, Wis., to conserve space and resources for the growing number of patients hospitalized with COVID-19. Residents of northwest Wisconsin have deviated from "essential" practices including wearing masks and maintaining distance, said Dr. Bobbie Gostout, chief executive of Mayo Clinic Health System.

"That really starts a vicious cycle of: There's more infection, but then there's still disregard for safe behaviors, so one person can infect more people," Gostout said.

In Minnesota, more intensive care unit beds were in use by the end of last week, and the state set a record Friday for total virus patients in the hospital. But there's still capacity, said Dr. Rahul Koranne, chief executive of the Minnesota Hospital Association, and medical centers haven't even tapped their surge capacity.

"I don't think the worry is the spaces available — at all," Koranne said. "Wisconsin is in a different spot than we are."

While higher case counts in Minnesota are coming on a much higher volume of testing, health officials say increased testing alone can't explain the growth in cases — especially since the share of positive tests continues to push higher, Dr. Matthew Prekker, an emergency and critical care medicine specialist at Hennepin Healthcare, said on Friday.

"The trends averaged over the past seven days make me think this is going to get worse before it gets better," Prekker said.

Deaths reported Saturday included 15 residents of long-term care. Since the start of the pandemic, Minnesota has seen 148,472 confirmed cases, 10,270 hospitalizations and 2,457 deaths.

The month of May saw the peak in reported deaths at 696 while the monthly low — 159 — came in July. The number of deaths reported increased in August and September before nearly doubling in October.

Not all death certificates for those who died in October have been finalized. A Star Tribune analysis of available records shows that nearly two-thirds of those who died during the month were more than 80 years old. Four people under age 50 died of COVID-19.

In recent weeks, health officials have emphasized growing COVID-19 case rates in counties outside the Twin Cities metro area. The shift shows in the October death records, which include the first fatalities reported at Tuff Memorial Home, a long-term care facility in the southwest Minnesota town of Hills.

"We were doing good for so long," said Eli Ripley, the facility's administrator. "It just sort of reared its ugly head — it can hit any nursing home at any time."

CentraCare's hospital in St. Cloud saw more COVID-19 deaths in October than any previous month, an increase that reflects a spike in the number of central Minnesota patients needing hospital care, said Dr. George Morris, the health system's physician incident commander for COVID-19.

"What's a challenge to look at is November — our numbers and rates could be even worse," Morris said. "Right now, to have wave upon wave upon wave, without going back to baseline in between, we are getting slammed."

But at Minneapolis-based M Health Fairview, one of the state's largest health systems, the increase feels more like a "gradual uptick," said Dr. Erica Kuhlmann, a pulmonary critical care physician.

Kuhlmann says she's concerned that case numbers are staying high, but "we as a hospital system in the Twin Cities have contingency plan after contingency plan about what to do to take care of Minnesotans. I feel safe because I'm a part of that — I know the plans."

In St. Louis Park, the number of COVID-19 patients hasn't returned to the highs of this spring, but the recent "ramping up" should be a call to action, said Dr. Alexis Christie, a pulmonary specialist at Methodist Hospital.

"Continuing to do the boring but necessary masking, not having Thanksgiving, staying at home — it actually helps," Christie said.

The Upper Midwest was hit by two weeks of unusually cold weather in October, which forced many people indoors where the virus can spread more easily, Temte said. The surge in the region's case counts could be a preview, he said, of winter across the country.

"For the national perspective, I would characterize it as explosive," Temte said.

Advances with vaccine development, faster technology for diagnosing infections and experimental treatments for COVID-19 all provide reason for hope, said Dr. Mark McClellan, a health policy professor at Duke University. But their impact is still down the road, McClellan said, leaving a critical period of weeks and months when slowing the spread is key.

"We are facing some real challenges in the near future," said McClellan, a top health care official in the George W. Bush administration. "The good news is, we're better prepared than we were."

Data editor MaryJo Webster contributed to this report.

Christopher Snowbeck • 612-673-4744