More than 200 million Americans braced for an unusually brutal winter storm starting Friday. The storm is expected to sweep across much of the United States. The National Weather Service (NWS) warned of "extremely dangerous" conditions.

The storm tracked eastwards from the High Plains and Rockies. Heavy snow is predicted through the Southern Rockies and Plains, into the Mid-Atlantic and reaching the Northeast. Cities including Memphis, Nashville, Washington DC, Baltimore, Philadelphia and New York faced potential snowfall. The Arctic blast brought sub-zero temperatures and wind chills.

US transportation officials warned of weekend travel disruption. Airport authorities in major cities anticipated delays and cancellations. The NWS warned of a life-threatening risk of hypothermia and frostbite.

Winter storms are a recurring challenge in North America, impacting infrastructure and daily life. Similar weather patterns have been observed globally, from Siberian blizzards to European cold snaps, highlighting the universal challenges of extreme winter weather.

The storm's progress will be closely monitored. Further updates and safety advisories are expected.