So too did Winter Storm Juno, aka Snowmageddon, the monster blizzard now engulfing the north-east of the United States, start with a bewitching calm.

Since I moved to the city in mid-December - my first winter in the northern hemisphere - my new neighbours have bemoaned the "warm" weather. There was no white Christmas. Only the odd blast of sustained subzero weather. Compared to last winter's "polar vortex", it's been mild.

This is perhaps why there was a playful atmosphere in the air this morning as city parks were transformed into Narnia-like white landscapes, populated by kids taking their Christmas toboggans out for a rare spin. People huddled in warm coffee shops and watched the gentle flurries outside. It was a novel start to Australia Day for me, a world away from balmy Hottest 100 barbecues and Invasion Day protests.

. @NOAASatellites eyes developing US Nor'easter. Blizzard conditions expected http://t.co/PAvGkE2im1 #Snowmageddon2015 pic.twitter.com/QBf6AgAvKx — NASA (@NASA) January 26, 2015

But this morning's lashings of powdery white gave way to a heavy dump of snow this afternoon, slowing traffic to a crawl and disappearing parked cars. It will be a full-blown blizzard later tonight, which will wallop east coast states and bring huge metropolises to a standstill.

A state of emergency is in place across the east coast, with the storm affected to hit a swathe of the country from New Jersey to Maine.

Tens of millions of people in major cities are due to be affected. Heavy snowfall - up to  a metre in New York City - and wind gusts of up to 110 kilometres an hour are expected to bear down on parts of New York state as night falls.

"This is not going to be like other snowstorms," New York City Mayor Bill de Blasio warned residents this morning.

"It is going to be - by all indications - worse. And people have to be ready."

While some local media have mocked the doomsday-like warnings of the Snowmageddon - "NYC Mayor: 'Reconcile Yourselves With Your God, For All Will Perish In The Tempest' read a headline on The Onion today - the city is taking heed.

New York, which cliche tells us never sleeps, is settling in for a deep hibernation as night falls.

All non-emergency traffic has been banned from the roads after 11pm, with drivers facing $300 fines. The subway, the real arteries of this commuter metropolis, will limit services after 8pm, to protect trains from snow damage. All Broadway shows have been cancelled. Central Park is off-limits. Schools will be closed across town tomorrow. About 6600 flights have been cancelled, according to CNN.

#Snowmageddon2015 hits Yankee Stadium. Be safe out there. pic.twitter.com/EPQaLEjBmz — New York Yankees (@Yankees) January 26, 2015

In a city where the wealth disparity can seem overwhelming, where whole families beg for change on the subway, the most serious fears are for those without adequate heating and shelter. "Code Blue" procedures are in place for NYC, which means outreach services are stepped up and shelters cannot turn away the homeless.

Residents have been instructed to stock up and stay in. Since Sunday afternoon, long lines have stretched out the door of shops such as Trader Joe's grocery store as people hoard food, water and candles.

I visited a mall in downtown Brooklyn this morning, a last-minute attempt to buy snowboots that just hadn't been necessary until today. In shop after shop, the aisles were empty, cleared out by shoppers clearly savvier than me. I found myself alongside a fellow expat, a Kiwi, in the last shoe store I could find, staring at the last lone couple of pairs of gumboots. Not nearly adequate for the cold but we both agreed they would have to suffice.

NYC: Snow at about 2 inches per hour. Hard to see from the video, but it's coming down fast. #snowmageddon2015 https://t.co/bbiOZNHt9G — Andrew Nystrom (@adnys) January 26, 2015

Outside, snow is blowing in hard now, moving horizontally across the streets of my Brooklyn neighbourhood, clumping thickly on brownstone steps and burying garbage bins. Adding to the strangeness of it all, people are walking backwards down the footpath outside my window to avoid a sock of wet snow to the face. Police cars and mammoth snow plows are moving slowly up and down the streets, which are otherwise emptying of cars.

It's quiet again, but the day's calm has dissipated: there is a sense of foreboding in the air.

"Some storms come in a measured manner," de Blasio said this morning. "This is going to come in in a sudden spurt of activity. We saw some flurries this morning, and that has largely dissipated, but what you're going to see in a few hours is something that hits very hard and very fast, and people cannot be caught off guard."

"Recognise this as an emergency. It is not business as usual."

So all we can do is wait.