Cold and Snow: But How Harsh Was Winter, Really?

March 24, 2011 — -- Between the extreme cold temperatures and a set of punishing snowstorms that repeatedly brought havoc to a good chunk of the eastern United States, it was a tough winter for some.

Take Nowata, Okla., for example, where temperatures in February dropped to a record 31 degrees below zero. When December lows dipped to just 31 degrees above zero, Sarasota, Fla., broke a cold-temperature record that had stood for 82 years. And in February, an Arctic blast drove Laramie, Wyo., temperatures down to a bone-chilling minus 61 degrees.

In terms of long-term temperature trends, however, just how much did Old Man Winter's wrath hit this time? Apparently, not so much.

"The last two winters being a bit colder than normal has generated a lot of headlines. But in the longer historical perspective, they're really not very exceptional," said James Hurrell, a senior climate scientist at the National Center for Atmospheric Research in Boulder, Colo.

Hurrell has just completed a new temperature analysis that shows winter of 2010-2011 was, on average, warmer than you might think -- ranked as only the 39th-coldest winter in the U.S. since 1895.

Tell that to millions of Americans who shivered through extended periods of bitter-cold over the last few months.

"It was colder than normal," in some places, Hurrell said. "But those cold regions were balanced by some very warm regions in other parts of the country."

Areas of the southwestern U.S., for example, along with parts of Alaska recorded warmer-than-average winter temperatures, according to the National Climatic Data Center in Asheville, N.C.

A vast majority of climate scientists say that -- despite natural short-term weather events that can bring wild swings of cold and warm -- long-term climate trends continue to show a gradual warming currently taking place globally, consistent with human-caused climate change.

"We are in a warming climate," said Richard Somerville, a climate scientist and distinguished professor emeritus at the Scripps Institution of Oceanography who also has served as a lead author for the Intergovernmental Panel on Climate Change. "The long-term trend is about a third of a degree Fahrenheit increase per decade."Perceptions that the past winter was colder than normal were driven partly by the fact that record amounts of troublemaking snowfall were recorded across parts of the Midwest and Northeast.

New York City, for example, was hit by eight snowstorms that dumped at least 36 record-breaking inches of snow.

"We've had snow on the ground since the second week of November," said meteorologist Chikage Windler with ABC affiliate KSTP-TV in Minneapolis-St. Paul. "Everybody's like, 'This has been a horrible winter since it's been so cold and so snowy.' The reality is cold temperatures really haven't been that impressive."

Windler said the average temperature for December, January and February pegged the Twin Cities' winter as the 36th-coldest on record.

Scientists said periods of extreme cold over the last few months can be partly blamed on a weather phenomenon called the Arctic Oscillation. From about mid-November to mid-January, however, shifting weather patterns involving the Arctic Oscillation helped frigid air spill into lower latitudes and much of the eastern U.S.

"That's what contributes to these very cold wintertime outbreaks," said Hurrell. "That's what we witnessed almost all winter long."

So what does that mean for the future? Scientists now are studying how factors like significant reduction of sea ice around the North Pole may be affecting Arctic Oscillation behavior and whether that could bring colder winters in coming years. But, scientists said, research in the area is still very preliminary and Arctic Oscillation patterns are difficult to predict.What we can count on, said scientists, are winters that will continue to become gradually warmer over time despite occasional cold spells.

"As the climate is warming, the number of record highs is outpacing the number of record lows" by about 2-to-1, said Hurrell.

ABC News information specialist Nicholas Tucker contributed to this report.