Massive winter storm expected to bury much of US in snow and ice

A powerful blast of cold air from the Arctic is expected to sweep through much of the United States, bringing snow and ice to nearly 30 states and affecting nearly 160 million people, forecasters warn.

The cold front is expected to ramp up on Thursday in the southwest, before pushing into the East Coast over the weekend.

Meteorologists say temperatures could plunge well below freezing in some areas as the frigid northern air, known as the Polar Vortex, settles over the country.

Transportation officials, including airport authorities in several major cities, are warning travellers to brace for significant delays amid the severe winter weather.

The weather system is expected to take shape in Texas and New Mexico before moving eastward, blanketing cities including Memphis, Nashville, Washington DC, Baltimore, Philadelphia and New York with snow.

Forecasters say states across the interior plains could see temperatures plunge to -40F (-40C) or even lower. Rocky Mountain states can expect to see large amounts of snowfall by Friday.

While it remains too early to predict exact snowfall totals in urban areas, some places are expected to see over 12in (30cm), weather experts say.

States further south may experience freezing rain, which could coat trees with ice and weigh them down, possibly leading to power outages.

The National Weather Service (NWS) has warned that wind chills could reach well below average, creating conditions in which exposed skin could suffer frostbite within minutes.

"With the extreme cold temperatures, expect prolonged snow and ice impacts which may include hazardous travel conditions, power outages, tree damages, snow-covered roads, and reduced visibility," the NWS said in its forecast.

Governors in several states, including Texas, North Carolina and South Carolina, have declared states of emergency, allowing emergency officials - including National Guard troops - to begin mobilising response efforts.

"Based on current forecasts, the State of Texas is acting to ensure Texans have the resources they need before severe winter weather impacts communities across Texas," Texas Governor Greg Abbott said in a statement.

The warnings come amid memories of the bitterly cold winter storm that struck Texas in 2021, causing the energy grid to fail and leaving millions of residents without power for several days.

Officials caution the cold temperatures could again cause pipes to freeze and then burst.

Roadways could also be blocked for days, especially in southern states with limited de-icing equipment.

Cold temperatures are expected to persist into next week.