Winter storm covers half of the US
A fearsome storm has spread a smothering shroud of white over nearly half of the US, hitting transportation, burying parts of the Midwest under 2ft of snow and causing at least 12 deaths.
Tens of millions of people stayed home and the hardy few who ventured out faced howling winds that turned snowflakes into face-stinging needles. Chicago's 20in of snow was the city's third-largest amount on record.
The storm that resulted from two clashing air masses was rare for its size and ferocious strength, with National Weather Service meteorologist Thomas Spriggs describing the event as "something we'd see once every 50 years - maybe".
Across the storm's path, lonely commuters struggled against drifts up to 4ft deep in eerily silent streets, with thick coats and ski goggles normally reserved for the slopes becoming essential for getting to work.
The storm promised to leave a blast of bitter cold in its wake, with overnight temperatures in northern parts of the Midwest expected to fall as low as minus 30C, with wind chills dropping to minus 35C.
The 12 fatalities included a homeless man who burned to death on New York's Long Island as he tried to light cans of cooking fuel, and a woman in Oklahoma City who was killed while being pulled behind a truck on a sledge that hit a railing.
Airport operations slowed to a crawl across the US, and flight cancellations reached 13,000 for the week, making this system the most disruptive so far this winter. A massive post-Christmas blizzard led to about 10,000 cancellations.
In the winter-weary north east, thick ice caused several structures to collapse, including a petrol station canopy on Long Island and an airplane hangar near Boston.
Chicago schools cancelled classes for a second straight day, and the city's iconic Lake Shore Drive remained shut down, nearly a day after drivers abandoned hundreds of snowbound vehicles.
Elsewhere, utility crews raced to restore power to many thousands of homes and businesses in Ohio, New Jersey and Pennsylvania, where freezing rain and ice brought down electrical lines. Rolling blackouts were implemented across Texas, due to high demand during a rare ice storm.