From the Palmer Divide to the Plains on Wednesday, an exceptionally powerful “bomb cyclone” brought 100-mph wind gusts and conditions rivaling those of a hurricane, except with blinding snow in places.

The cyclone of “historic proportions,” according to the National Weather Service, is racing into the upper Midwest. Blizzard conditions, which stranded more than 1,000 motorists in Colorado on Wednesday and shut down Denver International Airport, continue to plaster parts of the Dakotas and northwest Minnesota.

A severe-storm threat extends on the massive cyclone’s south and east sides, from northern Mississippi and Alabama into southern Michigan. Tornado watches covered parts of seven states.

A rare “bomb cyclone” is expected to cause extreme weather across the central U.S. (Adriana Usero/The Washington Post)

“Major damage” was reported from a tornado near Paducah, Ky., on Thursday morning. The twister narrowly missed the Weather Service office in Paducah, requiring meteorologists to seek shelter while the service’s office in Louisville briefly took over operations.

In the transition zone between the warm and cold sectors of the storm, the combination of downpours and melting snow poses a flooding threat in eastern Nebraska and Minnesota, southeast South Dakota, Iowa, Wisconsin and northern Michigan. Ice jams are a major concern along rivers in this region.

By Friday, the storm’s effects on the Lower 48 are expected to turn tamer as it lifts into northeast Canada. Mainly just rain showers are expected as the storm’s cold front pushes toward the Eastern Seaboard.

But the storm will leave behind a remarkable and, in some areas, destructive and costly legacy.

On Tuesday and Wednesday, the storm came in phases, transitioning from violent thunderstorms on its southern flank to a full-fledged blizzard on its north and west sides. In the middle, soaking rain on top of snowfall and icy rivers led to flooding.

An enormous area was buffeted by powerful winds, exceeding 100 mph in a few spots.

The storm began with a broken line of severe thunderstorms that swept from eastern New Mexico to eastern Texas late Tuesday night and early Wednesday. Three tornadoes touched down, including an EF-2 near Dexter, N.M. The National Weather Service in Albuquerque called the tornado — which stayed on the ground for 15 miles — the “earliest known EF-1 or stronger tornado in the state.” Baseball-size hail pummeled Ward County, Tex.

Individual storms and clusters merged into a violent squall line that left a 500-mile-long path of wind damage as far east as Dallas. A gust of 78 mph was measured at Dallas-Fort Worth International Airport, while gusts at nearby Texas weather stations in Grand Prairie and Granbury hit 80 mph. A “logistics facility” at the airport was partially unroofed, the debris landing on and damaging multiple vehicles, according to the Weather Service, while an Amazon warehouse’s roof was peeled off.

Barometric pressures continued to fall as the storm system rapidly “deepened” Tuesday night. Temperatures in Denver dropped from 62 degrees Tuesday to 26 degrees by lunchtime Wednesday, light rain transitioning to a heavy, wet snow. The cement-like paste quickly made roads impassible. As winds cranked up, visibility dropped to near zero.

Despite pleas from the Weather Service that motorists “could become stranded” if they ventured out, more than 1,000 were trapped by the conditions, according to CNN. Colorado Gov. Jared Polis (D) activated the National Guard, which rescued more than three dozen people stuck in the treacherous conditions.

“We’d have to go . . . way back to find something that matched the wind aspect of this event,” said Greg Hanson, warning coordination meteorologist at the National Weather Service in Denver. “It’s Colorado. We can handle the snow. But the wind has been extremely impactful.”

The heftiest snow came down in the mountains, with Wolf Creek Pass along Highway 160 reporting 45 inches. Fourteen inches piled up in Cheyenne, Wyo., its fourth-heaviest single-day snowfall on record.

Officially Denver International Airport picked up only 7.1 inches of snow, but blowing and drifting contributed to the disaster that unfolded on area highways Wednesday afternoon.

“One volunteer group was out all night rescuing stranded motorists,” Hanson said. “Nobody really stopped.”

Winds gusted to 80 mph at the airport while visibility dropped to 0.13 miles just before 2 p.m. Wednesday. The airport reported wind gusts topped 57 mph for six straight hours.

“It’s only the fourth time I can remember that the Denver airport has shut down all four runways,” Hanson said.

Nearby Centennial Airport recorded winds gusting to near 70 mph along with thundersnow and freezing fog around noontime.

Seventy miles to the south, Colorado Springs Airport recorded gusts up to 97 mph amid blinding whiteout conditions.

Power outages were also an issue, Hanson said. At the height of the storm, Xcel Energy reported over 400,000 customers in Colorado were without electricity.

“It was a very well-predicted storm,” Hanson said. “We’re pleased by how our forecasters handled it, and the media has been great in getting the word out.”

Models had hinted this storm would become a meteorological “bomb,” its central barometric pressure dropping 24 millibars or more in 24 hours. After a bout of rapid intensification, many locations recorded air pressures rivaling those of a Category 2 hurricane. Typical fair-weather air pressure is about 1010 to 1015 millibars.

Pueblo, Colo., unofficially dropped to its lowest air pressure on record. The lower the pressure, the more intense the storm. It’s an indicator that the atmosphere weighs less over a given location, the removal of air creating a vacuum effect. That sucks in surrounding air and results in damaging winds.

Lamar, Colo., may set a state record with its 970.4-millibar pressure reading.

Dodge City, Kan., also recorded its lowest pressure in the past century.

The incredible pressure gradient across the region meant damaging winds would continue across most of the High Plains and mountains.

Winds hit 103 mph in Pine Springs, Tex., and 104 mph in San Augustin Pass, N.M., while gusts in a number of locations across Colorado hit 90 mph. Winds gusted to 85 mph in Weskan, Kan., 89 mph in Hemingford, Neb., 80 mph in Amarillo, Tex., and 74 mph in Gage, Okla.

The winds toppled high-profile vehicles in Texas and, in Logan, N.M., blew 26 rail cars off a bridge. No injuries were reported from the incident.

While the severe storms, blizzard and high winds captured most of the storm’s headlines, its heavy rainfall led to serious flooding and ice jams where the snow transitioned to rain in eastern Nebraska and South Dakota, as well as in western and central Iowa.

“The Highway Superintendent in Yankton County says 75% of the roads in the county are either under water or have water running over them in spots,” tweeted Tom Hanson, an anchor for KDLT in Sioux Falls, S.D.

The Des Moines Register reported “30-foot ice slabs” flowing down rivers, damaging a bridge, and “severe flooding problems” that closed highways and roads.