As a massive snow storm grips the eastern United States, some scientists and meteorologists are wondering whether there is a single, overriding reason for this winter's extreme and sometimes violent weather.
"Just like different seasons of the year, we believe the weather is also cyclical," says Bernie Rayno, senior meteorologist at AccuWeather.com.
Rayno and others at the company, using today's advanced technology, have researched weather patterns from previous decades for a pattern that knits them together and reached a conclusion about the current weather.
"We believe the weather pattern we are currently in is very similar to what we saw in the 1940's, '50s and '60s; that is, a log of extremes," says Rayno.
He looks not just at today's snowstorm, but at the entire weather picture for the past year -- hurricanes, tornadoes, mudslides in California and bitter cold in the Midwest.
"The overall weather pattern we see over a given amount of time, a given amount of years also fluctuates," says Rayno. "And right now we do believe we are in a cycle that will lend itself to a lot of extremes over the next five to 10 years."
It is reminiscent, he says, of what happened in those earlier decades. In 1947, for example, New York City suffered one of its worst blizzards ever, 25 inches of snow that paralyzed the city for days.
Newsreel pictures from 1947 show Manhattan island at a standstill -- streets clogged with snow, buses stopped in mid-route, the streets absent of people. It is a scene that repeated itself in other cities and other years for the next decade, one reason baby boomers may be correct in their recollections that winter used to be much harsher for them than their children.
"It does remind you of an old-fashioned winter," says meteorologist Joseph D'Aleo, who woke this morning in New Hampshire to a temperature of minus 11.
But scientists say it's not just the winter. They link this year's powerful hurricanes and periods of flooding to the decades of the '40s, '50s and '60s when there was serious flooding and devastating hurricanes, such as Hurricane Carla in the '60s.
So what is similar to those earlier decades? For one thing, say the two meteorologists, there is no El Nino effect. El Nino is the warming of the Pacific near the equator, which effects weather activity.
Rayno says there is a weak El Nino this winter, but, "it's not overwhelming things."
What Rayno and others are watching is the Atlantic Ocean, where water is warmer than normal.
"When you get those [temperatures] warmer than normal, you tend to get low pressure off the eastern seaboard," he says.
"You bring down cold, dry air," Rayno adds, "which is one of the main ingredients that you need for snowstorms."
D'Aleo makes another point.
"The Atlantic Ocean has warmed significantly since the middle 1990s, and that has led to significant storms in winter and an increase in the hurricane activity," he says.
In essence, the warmer Atlantic cannot block storms the way an ocean with colder water does -- and that means increased rainfall, more hurricanes and more severe winter weather as part of a new long-term cycle.
But many other scientists disagree.