Nature's Notebook

To many people here in the Northwest Corner, this has been the winter that isn’t. Until the cold snap arrived in mid-January, temperatures were reaching record highs, and we have yet to see more than a tantalizing dusting of snow so far this season.

As reported in The Lakeville Journal two weeks ago, ski areas and other businesses dependent on winter sports have been hard hit by the weather. The words "global warming" are on more than a few people’s lips.

It so happens that a more mundane phenomenon than global warming may explain this non-winter’s weather:

El Niño. (Though, to be fair, it would be unwise to dismiss global warming as a factor in long-term climate developments, such as the overall trend toward warmer winters in the past several decades and the increased number of extreme weather events worldwide.)

El Niño, as most people know by now, is a cyclical rise in ocean surface temperatures in the equatorial Pacific. The last "major" El Niño event was in the winter of 1997-98, although there have been at least two smaller events since. According to Gary Lessor, assistant director of Meteorological Studies at Western Connecticut State University in Danbury, this winter has seen a moderate El Niño.

During an El Niño, explains Lessor, the jet stream has a more dominant east-west flow than in normal years. (Think of the jet stream as a dividing line between warmer air to the south and colder air to the north.) The stronger east-west flow of the jet stream in an El Niño year generally stays to the north and prevents cold arctic air from moving southward, as it normally would, causing us to have warmer than average winters.

This is pretty much what happened this year, until the jet stream finally shifted southward a couple of weeks ago. This, Lessor says, coincided with the peaking of the El Niño event in mid-January. As for the rest of the season, Lessor forecasts a continued return to average or slightly above average temperatures.

Our flora and fauna have apparently evaded serious impacts from the anomalous weather patterns. Russell Russ, a forester at the Great Mountain Forest in Norfolk, says that other than black bears being active well into late December, he has noticed nothing like the premature opening of cherry blossoms that occurred south of our region. In this column, I have mentioned the unusually high number of rare bird sightings in Connecticut, the latest being a lazuli bunting(a western songbird) that has been hanging around southeastern Connecticut.

’Tis the season to keep a close eye on your bird feeders and backyards.

Fred Baumgarten is a naturalist and writer. He can be reached at fredb58@sbcglobal.net. His blog is at www.thatbirdblog.blogspot.com.