A rare storm with hurricane-like, 100-mph winds left more than a million people without power Monday as it wreaked havoc across much of the Midwest — battering Chicago as the city recovered from a night of chaos and widespread looting.

The derecho — which has the strength of a hurricane but hovers over a far wider area — flattened homes and flipped over vehicles as it spent several hours leaving a trail of damage from eastern Nebraska across Iowa and parts of Wisconsin and Illinois.

By Monday night, PowerOutage.us reported more than 1.1 million people without power due to the storm — with more than 570,000 in Illinois.

“It ramped up pretty quick,” said Patrick Marsh, science support chief at the National Weather Service’s Storm Prediction Center.

“I don’t think anybody expected widespread winds approaching 100, 110 mph,” he said.

A derecho often causes more damage than even a tornado because it can hover in one place and its high winds can affect a far larger area, Marsh said.

Winds of 100 mph can stretch for “20, 30, 40 or God forbid, 100 miles,” he said.

What happened Monday morning was the result of unstable, very moist air that had parked for days over the northern Plains — culminating  in a derecho.

“They are basically self-sustaining amoebas of thunderstorms,” said Northern Illinois University meteorology professor Victor Gensini. “Once they get going like they did across Iowa, it’s really hard to stop these suckers.”

He compared it to a devastating super derecho of 2009, which was one of the strongest on record and traveled more than 1,000 miles in 24 hours, causing $500 million in damage, widespread power outages and killing a handful of people.

“This is our version of a hurricane,” said Gensini, who added it was one of the strongest in recent history and predicted it would prove to be one of the nation’s worst weather events of 2020.

As Chicago recovered from its depressing night of looting, residents were warned by the National Weather Service of winds of 80 to 90 mph.

“This is an extremely dangerous line of storms. … Stay away from windows and head indoors immediately if walking near high-rise buildings,” the service warned.

“Make preparations NOW, don’t wait for the storms to arrive.”

The city experienced its most severe winds at about 4 p.m. with a 72-mph gust recorded at Midway Airport.

The National Weather Service tweeted that “much of northern Illinois has pockets of damage with downed trees, debris, and power lines blocking roadways” after the worst had passed.

After blitzing Chicago, the storm moved east, and a severe thunderstorm watch covered much of southwestern Michigan and northern Indiana until midnight.

A flood warning was issued for Lake Michigan over fears the derecho would generate large waves and push water ashore.

Several people were injured and widespread property damage was reported in Marshall County in central Iowa after 100-mph winds swept through the area, said its homeland security coordinator, Kim Elder.

Elder said winds blew over trees, flipped cars, downed power lines, ripped up road signs and tore roofs off buildings, some of which caught fire.

“We had quite a few people trapped in buildings and cars,” Elder said, adding that the extent of injuries was unknown and no fatalities had been reported. “We’re in life-saving mode right now.”

Marshalltown Mayor Joel Greer declared a civil emergency, telling residents to stay home and off the streets so that first responders could respond to calls.

Roof damage to homes and buildings was reported in several Iowa cities, including the roof of a hockey arena in Des Moines.

Photos showed semi-trailers flipped over or blown off highways.

MidAmerican Energy Company spokeswoman Tina Hoffman said downed trees made it difficult in some locations for workers to get to power lines. In some cases, power line poles were snapped off.

“It’s a lot of tree damage. Very high winds. It will be a significant effort to get through it all and get everybody back on,” Hoffman said. “It was a big front that went all the way through the state.”

Cedar Rapids, Iowa, had “both significant and widespread damage throughout the city,” said public safety spokesman Greg Buelow. Tens of thousands of people in the metro area were without power.

“We have damage to homes and businesses, including siding and roofs damaged,” he said. “Trees and power lines are down throughout the entire city.”

Cedar Rapids on Monday night issued a 10 p.m. curfew that will continue until further notice, as crews worked to clean up fallen debris.

The power outages were particularly alarming given the high heat across the region.

With people with medical conditions — heightened by the coronavirus pandemic — “it becomes dire pretty quickly,” Marsh said.

With Post wires