Why is this blizzard so...blizzardy? The science beneath the snow.
Conditions are just about perfect for snowfall and wind over the East Coast on Tuesday and Wednesday, thanks to a sudden drop in pressure produced by colliding air masses.
East Coast folks: Stock up on munchies, get those prescriptions filled and get ready to hunker down for the next day or two.
A huge nor'easter, dubbed Juno, is expected to batter the East Coast starting tonight (Jan. 26). The corridor from New York to Boston is expected to get between 1- 2 feet (0.3 to 0.6 meters) of snow, with some areas potentially receiving up to 3 feet (0.9 meters) of snow. In addition, winds will gust up to 60 to 70 miles per hour (96 to 113 km/h) in some places along the coast, making this a dangerous blizzard, said Patrick Burke, a meteorologist with the National Weather Service's Weather Prediction Center.
The monster snowstorm is occurring because of a perfect confluence of factors, including a low-pressure system that is traveling just the right path along the coast, Burke said. [The 10 Worst Blizzards in U.S. History]
The Northeast gets some of the largest winter storms in the world, which occur when the frigid air blowing across the North American continent collides with the balmier breezes over the Atlantic Ocean. In particular, a process called bombogenesis, where air pressure drops by about 24 milibars or more in a 24-hour period, can produce intense storms, or "bombs," like Juno.
"Where the two meet you can get this explosive development of low pressure, which must mean that the low pressure is deepening very rapidly," Burke told Live Science.
That, in turn, allows the air low in the atmosphere to rise. As rising air cools, moisture condenses out as either rain or snow, Burke said. The low-pressure systems in the region also tend to create strong northeasterly winds — hence the name nor'easter, Burke said.
In the case of Juno, which is expected to hit this afternoon and continue until tomorrow afternoon (Jan. 27), conditions are perfect for a heavy snowfall and blustery winds.
At this time of year, the air over the continent is already quite cold, creating a large contrast with the warmer coastal air and providing a quickly developing low-pressure system. These conditions also ensure that all the precipitation will land in the form of snow, rather than the wintry mix of rain and snow that is more typical for the region, Burke said.
In addition, this snowstorm is likely to follow just the right trajectory at just the right time to create lots and lots of snow, with the coastal-low pressure front expected to develop a little more inland than is typical, Burke said.
This storm is a blizzard, or a snowstorm where wind gusts frequently reach 35 miles per hour (56 km/h) and visibility is reduced to less than 0.25 miles (0.4 km).
"A heavy snowfall can actually be kind of a pretty thing to watch but when you include all this strong wind, then it becomes very dangerous and life threatening," Burke said. "Your visibility is reduced to near-zero."
People caught in those conditions can quickly lose their way, become disoriented and freeze to death, Burke said.
People in affected areas should make sure to stock up on provisions, fill their prescriptions, and be prepared to sit tight in their houses for the next day or two, Burke said. Then, once the snow settles, they can enjoy the winter wonderland.
One way to reduce the hassle after the storm is to clear the driveway of obstacles (such as cars) that will create giant snowdrifts. People can also reduce their after-blizzard work by letting wind carry snow into a neighbor's yard before taking out the shovel, Ryan Maue, a meteorologist at Florida State University, said via Twitter.
Editor's Note: This story was updated to add information about bombogenesis, the process by which intense storms such as Juno may form.
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