A derecho, characterized by a line of thunderstorms producing severe winds and damage over a large area, swept across the Northern Plains and Upper Midwest.

Plumes of smoke are blanketing large swaths of the U.S. and parts of Europe, presenting risks for those breathing it.

Tornadoes and violent storms have struck parts of the South and Midwest, killing at least one person, knocking down power lines and trees, ripping roofs off of homes and shooting debris thousands of feet into the air.

As near temperatures climbed to near records in parts of the central United States, a potent storm system was setting up to wallop the nation later.

Since the middle of November, the entire region has returned to levels similar to those seen in October. Governors have used the declining numbers to justify their divergent approaches to fighting the pandemic, even jousting at times. As the pandemic crept into communities across the Midwest, more people had loved ones, friends or acquaintances fall ill or die. Many health experts warned that the region was ripe for widespread infections, especially as the weather cooled and people gathered inside, making it easier for the coronavirus to spread. Other experts say some pockets of people, such as those who work in meatpacking plants where infections were widespread, had experienced such high rates of infections that the virus has slowed.

Now the coronavirus outbreak is heating up fast in smaller cities in the heartland, often in conservative corners of America where anti-mask sentiment runs high. Wisconsin is averaging more than 2,000 new cases a day over the last week, compared with 675 three weeks earlier. Health officials said if virus cases in these neighborhoods continue to build, the city might roll back the reopening in some places and require businesses to close back down. In Joplin, Missouri, a mask ordinance was allowed to expire in mid-August as virus fatigue grew. Since then, the number of positive cases there and in surrounding Jasper County — a deeply conservative county that Trump won by more than 50 percentage points over Hillary Clinton in 2016 — has risen about 80%.