At least seven people have been killed in several states as US Midwest has been hit by a cold snap known as a polar vortex.

The arctic weather made temperatures to fall to -22F in Chicago – colder than parts of Antarctica – and -25F in North Dakota.

Freezing weather will chill 250 million Americans, and 90 million will experience 0F or below.

On January 30, snow is expected to fall from the Great Lakes region into New England. As much as 24in is forecast in the state of Wisconsin, and 6in in Illinois.

States of emergency have been declared in Midwestern Wisconsin, Michigan and Illinois, and even in the normally warmer Deep South states of Alabama and Mississippi.

The National Weather Service (NSW) is warning frostbite is possible within just 10 minutes of being outside in such extreme temperatures.

Polar Vortex freezes parts of US

Grand Forks, North Dakota, has seen the lowest wind chill so far at -65F on January 30.

Twenty million people in the continental US are expected to experience temperatures of -18F or lower by the week’s end.

On January 30, two Michigan residents were found dead in their neighborhoods, the Associated Press reported.

Officials say one may have become disoriented and wandered into the cold without proper attire.

On January 29, a 55-year-old man froze to death in a Milwaukee, Wisconsin, garage, with the medical examiner’s office ruling he “apparently collapsed after shoveling snow”, local media reported.

In Pekin, Illinois, an 82-year-old man died from hypothermia outside his home, NBC News reported.

On January 28, a 75-year-old man was killed by a snow plough near Chicago.

In northern Indiana, a young couple died after a collision on icy roads.

The US Postal Service has called a halt to mail deliveries in parts of 10 states in the Great Plains and Midwest.

Hundreds of schools, as well as colleges and universities, have been closed in the affected states.

Beer deliveries in Wisconsin have been hit, too, as brewers delay shipments for fear their beverages will freeze in the trucks.

Weather officials in the state of Iowa have warned people to “avoid taking deep breaths, and to minimize talking” if they go outside.

Farmers across the Midwest have been taking measures to protect their livestock, including building igloos for chickens.

Animal rights organization PETA has warned people to bring pets indoors.

Meanwhile, police in the Illinois county of McLean had some fun, announcing that Elsa from the Disney movie Frozen had been arrested.