A winter storm on Saturday whipped up record-setting tides higher than during Superstorm Sandy, causing major flooding in New Jersey and Delaware after dumping nearly two feet (60 cm) of snow on the suburbs of Washington, D.C.
The heaviest snow engulfed New York on Saturday and was not expected to stop until Sunday, when up to 30 inches may have piled up in the nation's largest city, said New York Mayor Bill de Blasio.
More than 85 million people in at least 20 states were covered by a winter-weather warning, watch, or advisory, the Weather Channel said, and many stores were left with bare shelves as residents stocked up on food, water, and wine, preparing to spend the weekend indoors.
As of early Saturday morning, Boswell, Pennsylvania, had gotten the most snow with 23.5 inches,according to the Weather Channel. There was more than a foot of snow in Kentucky, Maryland, New Jersey, North Carolina, West Virginia, Virginia, and eastern Tennessee.
Nearly 160,000 customers in 13 states had no power because of the storm as of late Saturday morning, according to CNN.
The situation was particularly bad in Washington, D.C., which got reports of thundersnow and accumulations of more than a foot, according to Capital Weather Gang.
As of Friday night, nine deaths had been tied to bad roads and ice, according to The New York Times. States of emergency were declared in Maryland, Virginia, North Carolina, Georgia, Pennsylvania, Delaware, New Jersey, West Virginia, Tennessee, New York, and Kentucky. Washington has declared a snow emergency.
Tides higher than those caused by Superstorm Sandy caused major flooding along the Jersey Shore and Delaware coast and set records in Cape May, New Jersey, and Lewes, Delaware, said NWS meteorologist Patrick O’Hara.
A high tide of 8.98 feet was recorded at 7:51 a.m. Saturday at Cape May – slightly higher than the record of 8.9 feet previously set by Sandy on Oct. 29, 2012. A high tide of 9.27 feet was recorded at Lewes, higher than the 9.2 high tide recorded in March 1962.
"All the factors that affect the tides, it’s all happening at once," O’Hara said.
Nearly 5,000 flights were canceled Saturday, and another 1,000 flights due to go out on Sunday were also canceled, according to flightaware.com. The D.C. metro shut down service at 11 p.m. EST Friday, and planned to remain closed through Sunday.
The same storm system has also brought severe weather to the Gulf Coast, from Texas to Florida.
So what caused this weekend's monster snowstorm?
Snowstorms in January certainly aren't rare. But what's unusual about this one is how far in advance it was predicted. Unlike with most major storms, almost all the major weather modelswere in agreement that this storm was coming almost a week before it hit.
The only differences were in how much snow it would bring.
Moreover, this storm is just one of many similar storms we've seen in the past. We call them nor'easters because the wind is blowing from the northeast when it hits. Nor'easters are a nasty breed of storm that hits during winter.
Here are some of the forces that brewed the first nor'easter of 2016:
An energetic upper atmosphere
The storm began on Thursday night over the Gulf of Mexico.
Cold air from the Arctic had descended upon the mid-Atlantic Ocean and combined with moist air from an unseasonably warm Gulf Stream (roughly 5 to 6 degrees Fahrenheit above averagefor this time of year).
As the cold Arctic air sank and the warm Gulf Stream air rose, it generated a churning action — producing energy in the atmosphere.
At the same time this was happening, winds from a nearby jet stream blew the storm-brewing mix toward the Gulf of Mexico where it caused severe thunderstorms in Louisiana, Mississippi, and other states Thursday night.
But that was just the beginning.
As the nasty mix made its way up the coast, it smacked into a layer of air over D.C. — that came down from Canada — at subfreezing temperatures. This subfreezing air basically acts like a snowmaker.
As the storm generates precipitation, rain falls through this freezing-cold-air layer, which transforms the rain to snow. But the worst part of it all, which makes this storm so epic, is that it's drawing from "nearly infinite reservoir of high humidity air," The Washington Post reported.
Moving from the south is a pocket of humid air that will help fuel the storm. That means lots and lots of snow for us.
It takes a lot of ingredients to make a nor'easter, and not all of them are straightforward.
Other factors at play
This winter saw an unusually strong El Niño — a natural weather pattern caused by surface heating in the Pacific Ocean, which is tied to unusual weather around the globe. This creates an abnormally strong jet stream, which provides energy for East Coast snowstorms, as Slate reported.
And finally, while it's hard to draw a direct link between weather and climate change, the warming trend may be partly to blame for the increase in severe storms like this one. As the planet warms, it's causing a rise in sea levels, especially in the Northeast. The warmer water adds more energy and moisture to the air, which help drive severe storms like this one.
While storm forecasting has come a long way, it's still not perfect. Take the "historic blizzard" that was forecast to hit New York City in January 2015, which was predicted to dump as much as 2 feet of snow on the city but only brought about 5.5 inches!
Reuters reporting by Barbara Goldberg.