The U.S. side of the Niagara Falls is pictured in Ontario, Jan. 8, 2014.
Winter Storm Hercules brought heavy snow and fierce winds to the Midwest and Northeast and has been blamed for at least nine deaths so far. Here, drivers in Cleveland battle high winds and heavy snowfall as they navigate on The Detroit Shoreway on Cleveland's West Side.NEWS: Snowstorm Slams U.S. Northeast
This satellite image taken on January 3, 2014 by the Suomi NPP satellite shows the blanket of snow that stretches from the Midwest across to New England.
The Washington Post/Getty Images
A pedestrian walks along Carroll Creek in Frederick, Md.PHOTOS: Blizzard Nemo Slams Into U.S. East Coast
Firefighters in Brooklyn, N.Y. dig out of their firehouse after Hercules deposited up to 8 inches of snow in the area.NEWS: 'Snowquester' Storm Seen from Space
Headlights of a car illuminate the street on Cleveland, Ohio's W. 112th St. after power was lost.Naming Nemo: How the Storm Got Its Name
A snow plow removes snow on a street near a statue put on a bench in New York.
Being in the doghouse isn't always bad, especially for this Brooklyn, N.Y. dog scooting into an actual doghouse, during the fun of newly fallen snow.PHOTOS: Winter Wonderland
A husky in Somerville, Ma., with snow-fearlessness in its genes, waits for its owner outside of a store.
A Brighton, Ma. resident takes his son and puppy to a dog park for some fun before the storm worsens.
A branch and its berries in St. Michael's, Md. bear up under the weight of Hercules.
A young man snowboards in Chicago's Humboldt Park. An unexpected look for a beach, but that's winter for you.
A Cleveland, Ohio resident clears snow in the Edgewater neighborhood of the city.
Twitter users, too, have been photographing the new year's winter weather. From Twitter user @GutterIsATool: @Discovery_News Here's a good #snowstorm pic from the NHL Winter Classic in Ann Arbor, MI.
From Twitter user @RiverROC1: #NORDHOUSE DUNES WILDERNESS, MANISTEE NATION FOREST, MICHIGANpic.twitter.com/zYca7K34Qx
From Twitter user @JPMajor: @Discovery_News 27" drifts in my back yard here in RI!pic.twitter.com/Oey5BKzaIj
Was the crisp bite of frozen air during this month's polar vortex a remembrance of winters past for Americans? According to weather data collected by one meteorologist, this taste of Arctic chill may be growing rarer.
The cold snap triggered by the polar vortex, the low-pressure weather pattern that rammed into the United States from the Arctic the week of Jan. 5, was pretty paltry compared to cold waves in the past four decades, said Bob Henson, a meteorologist at the National Center for Atmospheric Research in Boulder, Colo.
"If you look at the number of days it stayed cold all day and all night, this cold wave was much briefer than past cold waves," Henson told LiveScience. "There are many ways to measure a cold wave, but the brevity of this one just jumps out."
With warm temperatures quickly returning to states such as Oklahoma, which is in the 50s Fahrenheit (teens Celsius) this week, Henson recently decided to compare the length of the polar-vortex freeze to earlier cold snaps. He worked with data provided by colleague Brandt Maxwell of the National Atmospheric and Oceanic Administration.
For cities including New York, Atlanta and Chicago, this month's deep cold was much briefer than past cold waves, Henson found. The 1970s and the 1980s were the worst of the bunch, with Chicago suffering through 40 days of below-freezing temperatures at least one year during these decades.
"The evidence is anecdotal, but it does point to the interesting possibility that cold waves are getting shorter in the U.S.," Henson said.
While global warming plays a role in the shift from long, bitter cold snaps to shorter Arctic blasts, a climate pattern in the Atlantic Ocean called the North Atlantic Oscillation is also involved, Henson explained. The NAO influences wind direction and atmospheric pressure over the North Atlantic, changing winter storm patterns. The current NAO pattern directs heavy snowfall and severe cold toward the United States and Europe, Henson told LiveScience.
"With global temperatures and cold waves, we don't expect linearity," Henson said. "There's going to be some variability in the mix."
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This story originally appeared on LiveScience.com.