Days of winter freeze ahead for 3200km stretch of US, with the storm not peaking until Monday

A woman records the city skyline with her phone, bracing against the cold temperatures on the Brooklyn Bridge in the Manhattan borough of New York City yesterday. Bringing icy temperatures, Winter Storm Fern will bring heavy snowfall, power outages and travel disruption. Photo / Charly Triballeau, AFP

A massive winter storm in the United States was spreading heavy snow and ice across a 3200km stretch from the Southern Plains and Southwest to the East Coast.

It’s expected to render travel dangerous or impossible, could cause locally serious vegetation damage and may bring long-lasting power outages before ushering in life-threatening cold.

Winter storm watches stretch from eastern Arizona to Virginia and North Carolina and will be expanded all the way to the Delmarva Peninsula and southern New England. Significant accumulations of snow, sleet and freezing rain are likely.

Computer model simulations yesterday were coming into greater agreement, shifting the axis of greatest accumulation slightly northward. Thirty centimetres is possible in the heart of the main snow band, which will stretch from Oklahoma and Kansas through parts of the Tennessee Valley, Midwest and Mid-Atlantic.

Even Washington, DC, could be looking at 15 to 30cm - bringing the biggest snowfall in years.

To the south of the snow band, a strip of freezing rain will bring crippling ice accretions. Some places could see ice snapping tree limbs and yanking down wires.

In between, a messy mix is likely. And accompanying the system is a bitter Arctic airmass. That will be problematic for those who lose power - plus the ice won’t start to melt until late next week.

During the storm’s peak, expected on Monday NZT, around 55% of people living in the contiguous US are forecast to experience snow, sleet or freezing rain at the same time.

As that frigid air flows southward, it will meet an atmospheric river streaming from the Pacific Ocean and Gulf of Mexico, spawning the widespread winter storm.

It will be the biggest of the season so far, with its impacts made more severe by the brutal and long-lasting cold that will follow it.

“We’re about to witness a truly legendary winter storm setup in the Southern US later this week,” wrote Defence Department meteorologist Eric Webb.

Dangerous and long-lasting cold

Late January is typically the coldest time of the year across much of the US.

This year, the period will coincide with a record cold air mass, ushered southward from Canada by a lobe of the polar vortex. That’s a rare combination.

After the storm passes, temperatures will nose-dive, setting the stage for life-threatening cold in areas that lack power and heat.

This is especially the case in the corridor from Texas to the Carolinas, where the heaviest ice accumulations are currently expected.

Around 102 million people are forecast to experience subzero temperatures into Tuesday.

Temperature records are forecast to be neared, tied or broken across parts of 25 states.

Some of these records date to the 1800s, which highlights the extreme and unusual nature of the upcoming cold - especially when coupled with such a far-reaching and impactful winter storm.

This frigid pattern shows no signs of easing through to the end of the month.

Sign up to Herald Premium Editor’s Picks, delivered straight to your inbox every Friday. Editor-in-Chief Murray Kirkness picks the week’s best features, interviews and investigations. Sign up for Herald Premium here.