Rare snowstorm hits US south, with four deaths reported

A rare winter storm is bringing snow and freezing rain to parts of the US deep south, closing highways and airports in Texas and prompting a first-ever blizzard warning in southwest Louisiana.

Four people are thought to have died from cold exposure so far - two cases are being investigated as cold-related by Austin authorities in Texas, while two deaths from hypothermia were reported in Georgia and Milwaukee.

Up in the country's north, parts of New York state are being hit by another storm, blanketed by up to 18 inches of snow.

More than 2,200 flights within the US were cancelled on Tuesday, and 3,000 more were delayed, according to online tracker Flight Aware.

The Gulf Coast, where even flurries are a rare sight, will see historic snowfall, the National Weather Service (NWS) said on Tuesday, with an inch of snow or more expected to fall per hour from eastern Texas through the western Florida Panhandle.

The NWS has forecast "heavy" lake effect snow, advising residents to avoid travel if possible.

New York Governor Kathy Hochul announced Monday she had declared a state of emergency in a dozen counties in western New York as communities face the snow and extreme cold.

The mayor of Buffalo, Christopher Scanlon, declared an additional emergency on his own, shuttering City Hall and closing Route 5, the Buffalo Skyway because of blowing snow and other dangerous driving conditions.

Parts of Canada have also been hit by especially frigid winter weather, with extreme cold warnings throughout the provinces of Ontario and Quebec. With the wind chill, temperatures will be as low as -50C (-58F) in some areas.

In the US south, the highest snowfall total recorded by Tuesday afternoon local time was 10.5 inches in Rayne, Louisiana, according to reports from the NWS.

Temperatures are expected to fall well below January averages, and may surpass record lows stretching up from the coast into the Tennessee Valley.

Governors of several states, including Louisiana, Mississippi and Alabama, have also declared states of emergency in response to the unusual cold.

The storm now hitting the US south began in Texas on Monday evening, and was forecast to spread eastward through Wednesday morning along Interstate 10, a major highway in the region.

By Tuesday afternoon, the storm moved into Georgia, Florida's panhandle, and North and South Carolina.

State leaders and agencies scrambled to confront the atypical weather.

Florida Governor Ron DeSantis said Florida's infrastructure was "designed differently" than in states that regularly see snow.

"We're not used to walking in a winter wonderland here in Florida," he said.

DeSantis, like North Carolina Governor Josh Stein, urged residents to stay home.

The extreme weather, part of a bitterly cold air mass that has descended on the south and eastern US, is forecast to linger over the next couple of days.

Around 40 million people, primarily across the southern US, were under some type of weather hazard, Marc Chenard, a meteorologist with the NWS, told BBC's partner CBS News. Another 170 million people from the Rockies to points eastward were under an extreme weather warning or cold weather advisory.

Many school systems cancelled classes and Houston's two airports suspended flight operations.

The NWS cautioned that the rare storm could continue to cause "widespread" disruptions in both air and land travel for several days even after the snowfall stops.