tSpectrum Health, a major health-care system here, officials spent part of last week debating whether to move to “red status” in a show of how strained hospitals had become.

A flood of mostly unvaccinated covid-19 patients was arriving at emergency departments already packed with people suffering other medical issues, sending capacity to unprecedented levels. The only hesitation for Spectrum’s decision-makers? Data suggested the covid surge was not over.

“We don’t have a darker color,” said Darryl Elmouchi, president of Spectrum Health West Michigan. “So if we’re red now, what are we in two weeks?”

He and other leaders ultimately decided Thursday to make the change, upgrading the health-care system to the most serious tier for the first time since the pandemic began. In recent days, the state had emerged as a new covid hot spot, leading the nation in new infections and hospitalizations. By the end of last week, its seven-day average of new cases had hit a pandemic high. State leaders asked the U.S. Department of Defense to provide emergency hospital staffing to handle the surge — a request granted Wednesday.

Coronavirus cases are on the rise nationally, an unwelcome trend after leveling off earlier this fall. On Monday, the United States reported a seven-day daily average of just under 93,000 cases — an 18 percent jump from a week earlier, according to figures from a briefing by the White House covid-19 response team. Hospitalizations were also up, increasing 6 percent to about 5,600 patients admitted per day.

At least two dozen states have seen cases rise at least 5 percent in the past two weeks, with Michigan, Minnesota, New Mexico, New Hampshire and North Dakota each recording per capita jumps of more than 60 percent. Some highly vaccinated states, including Vermont and Massachusetts, were also seeing steep rises in cases.

The growing caseload across the country has raised the specter of another surge this winter — what would be the nation’s fifth. Expert opinions vary, but Amber D’Souza, a professor of epidemiology at the Johns Hopkins Bloomberg School of Public Health, said a surge seems imminent. This one, though, could prove to be much milder than last winter’s due to vaccines, boosters and therapeutics that were not available last year.

“We are absolutely heading into an additional wave this winter across the country that may hit at different times and it may be at different extents in different parts of the country,” she said. “The good news is that we really do have hope that the toll from this wave this winter will be much less than last winter.”