At least 12 people have died in brutal winter weather that is shattering records across the US.

Americans rang in the new year with freezing temperatures stretching across 90 per cent of the country. More than 100m people from Canada to Mexico were under wind chill warnings and advisories on the second day of the year, according to CNN.

For some, the winter chill proved deadly.

At least six suspected cold-related deaths were reported in Wisconsin, where temperatures averaged 6.1 degrees Fahrenheit(-14C) between Christmas and New Years Day, according to the Milwaukee Journal-Sentinel. A 27-year-old woman died from cold exposure after injuring herself while walking to shore from a fish shanty on Lake Winnebago. A 57-year-old man was found dead after wandering away from a Veteran Affairs hospital in Madison.

Authorities in Bismarck, North Dakota found a dead body on a boat dry-docked near the Missouri River, after temperatures in the state dipped as low as minus 58 degrees(-50C) with wind chill. The man was believed to have died from exposure to the cold.

Flights delayed at Buffalo Airport due to heavy snow amid arctic U.S. weather

The cold snap was especially deadly for the homeless population. Authorities found the frozen body of a homeless man on a porch in Charleston, West Virginia. Another man was found dead in a trash bin in St Louis, Missouri, after the temperature dropped to minus 6 degrees (-21C).

States like Louisiana, Mississippi, and Alabama opened warming shelters to serve the homeless population. In Georgia, hospitals welcomed people suffering from hypothermia and other cold-related ailments off the streets.

"We have a group of patients who are coming in off the street who are looking to escape the cold – we have dozens and dozens of those every day," Dr Brooks Moore, the associate medical director in the emergency department of Grady Health System, told the Associated Press.

Tony Sampson tries to warm up by a fire under the Eastex Freeway in Houston, Texas, as temperatures drop (AP)

The fatalities extended to animals as well, as the National Weather Service (NWS) warned against leaving pets outside. The body of a dog was found curled up dead on a porch in Toledo, Ohio. Local Humane Society investigators told the Toledo Blade the animal was “frozen solid”.

In Massachusetts, at least three sharks washed up dead due to cold shock, according to the Atlantic White Shark Conservancy.

Harrisburg, Pennsylvania hit a record daily low of zero degrees(-18C) on Wednesday, and Sioux City, Iowa set a record low of minus 28(-33C) the day before, according to weather.com. The last week of 2017 marked the coldest last 7 days of the year for both Buffalo and Watertown, New York, the NWS reported.

Another cold front was expected to hit later this week.