Shot in the Dark

Although the past few days make it easy to forget, New York has experienced an unusually mild winter, with significantly higher temperatures and less snowfall than normal.

For the month of December 2006, the average temperature was 43.6 degrees Fahrenheit, a 6.3-degree departure from normal, and in January, New York received only 2.6 inches of snow, a figure that is 5.5 inches below the norm. On January 6, the highest January temperature ever documented in New York City-72 degrees Fahrenheit-was recorded.

According to David Rind, adjunct professor of earth and environmental sciences and NASA climate researcher, the primary reason for New York's nearly flurry-free winter is the effects of an El Nino system which has been affecting the weather since the fall.

"In general, when El Nino occurs, [which is] warming of the tropical eastern pacific, storms that would give us snow pass too far out to sea," Rind said. "That's what's been happening the past month or so."

However, according to Adam Sobel, associate professor of earth and environmental sciences and applied physics and applied mathematics, El Nino is not the only factor at work.

"You wouldn't expect a weak El Nino on average to make it as warm here as it has been by itself," Sobel said. "It could be a factor. ... Statistically, it's the right sign, but the magnitude is surprising."

Sobel attributes the warm winter to both El Nino and the North Atlantic oscillation, a phenomenon involving the fluctuation of different sea level pressures in the Atlantic Ocean that influences the strength and direction of westerly winds.

Although these effects are primarily responsible for the low snowfall, Rind said that it is important to note that global warming also contributed. "Without it [global warming], it would have been colder," he said. "With it, it's a little bit warmer."

Rind said that although New York's winter has been milder than average, it is not outside of normal weather patterns. "It's very variable from year to year," he said. "We've had winters with as low as just a couple inches in the whole winter."

Phenomena such as El Nino and the North Atlantic oscillation can also divert storms that appear to be approaching the East Coast. For Richard Bussert, manager of Columbia landscaping and grounds, this can mean preparing for a storm that never hits the city.

"Just because we haven't had any snow doesn't mean we haven't had any snow removal labor cost," Bussert said, recalling two incidents earlier this semester when he called in snow shovelers for a storm that never materialized.

"What we expect is eight significant snow or ice events during the course of the winter time," Bussert said. "And we really haven't had a significant event yet."