Bomb Cyclone Threatening More Than 70 Million People Across Central U.S.(Source Yahoo News)

Another winter storm is brewing and could affect upward of 70 million people living in the Central and Northern Plains and the Upper Midwest.

Known as the bomb cyclone, the storm starting Wednesday is expected to create hurricane-strength winds, blizzards, and flooding across parts of the central U.S.

More than 1,000 flights were cancelled Wednesday in preparation for the storm, with additional cancellations and delays possible. The majority of disruptions were for flights in and out of Denver International Airport.

Winter storm warnings are in effect in multiple states, including parts of Colorado, Wyoming, Nebraska, and South Dakota, CNN reports. The National Weather Service warned of heavy rains, severe thunderstorms, flooding, heavy snows, blizzard conditions, and heavy winds across the central U.S. over the next two days.

Storms are classified as bombs based on “how fast the atmospheric pressure falls,” The New York Times explains. For a storm to be classified as a bomb, the barometric pressure has to drop by at least 24 millibars over a 24-hour period.

Drops in atmospheric pressure aren’t uncommon and allow storms to strengthen while picking up more air. But when the pressure sharply falls by 24 millibars in less than a day, the storm is considered to be explosive, as Pop Sci reports. The official terminology for such a storm is explosive cyclogenesis, or bombogenesis.

The National Weather Service warned residents of Boulder, Colo. against traveling on Wednesday afternoon and evening, citing the possibility of icy roads, whiteout conditions, and strong winds, according to CNN.