Environmental Science - Essay Example

Nor’easters: Little known fury US hurricanes and tornadoes are known world over as the worst disaster wracking natural phenomenon, but little is known about equally furious nor’easters. Right from the times of Benjamin Franklin, studies on cyclones have taken place with deeper studies on hurricanes and tornadoes and good amount of data is also available on these cyclonic storms, but nor’easters are not so well studied. At times the high waves of strong nor’easters can cause damage to the extent or even exceeding that of a hurricane.

Nor’easters are known as weaker low pressure systems with winds rarely acquiring the strength of even the smallest hurricane. And even the general perception about them is that ‘they are less destructive than other storms’. For this very reason so little is known about nor’easters. Nor’easters are said to have caused heavy snow falls in New England and the Middle Atlantic states. In recent years, the US coastal areas have also been hit by a series of nor’easters. All this has led to more attention towards these storms.

Researchers have found that apart from their origins in atmospheric disturbances and their cyclonic winds, hurricanes and nor’easters bear little resemblance to each other. Hurricanes are warm-core systems and thus limited in height by the colder upper air, while nor’easters are cold-core systems that do not lose intensity with height. Unlike hurricanes, nor’easters do not necessarily form over the open ocean. Nor’easters are supposed to require the support of the jet stream to form, so their prevalence is closely related to seasonal changes in the position and the strength of the jet.

Correlation of data for the past 50 yrs suggest that the annual frequency of the strongest nor’easter is positively correlated with southerly jet-stream position over the eastern US. Wind’s speed, its duration and the distance are the three factors affecting the growth of waves. With an increase in any of these factors, the height of the storm surge increases. October to April is the primary nor’easter season with February being the most active month. Some of the features of nor’easters which can be summarized based on recent studies are;Because of their diffuse structure, they are difficult to characterize, categorize and predict.

Having not able to establish a direct relationship between a nor’easter’s wind speed and its destructive power has made the task of classification and comparison of these storms more difficult.Nonetheless, using wave data nor’easters have been divided into five categories from the common i.e. Class-I (weak) nor’easters to the, vary rare, Class V (extremely strong) nor’easters.It has been found that the overall frequency of nor’easters has changed significantly over the years. The key to determining the impact of nor’easters lies in studying how weather effects influence the waves produced by these storms, rather than solely what the storm’s pressure or wind speed be.

Researchers assert that one possible cause for the prevalence of major nor’easters in recent years is the availability of an atmospheric circulation pattern conducive to the formation of polar air masses over the Canadian prairies or the Arctic and the movement of these cold-air masses toward the southeast.Nor’easters are said to be most prevalent from January through March, primarily because of Hatteras and Gulf lows. The seasonality in the prevalence of severe and extreme nor’easters corresponds with the pattern of Bahamas and Florida lows as well as certain climatological aspects of North American Atmosphere circulation.

Preliminary studies, taken up recently, suggest that impact of a given storm depends, to a certain degree, on the physical characteristics of the coastal area involved. And with the increase of the population density along the Atlantic coast, nor’easters are bound to have an even greater impact upon the lives and livelihoods of coastal residents.