February 11, 2013. The main reason for the disaster — a cunning noristera (nor'easter), which incognito under the name of "Nemo", came from the south and shifted along the Atlantic coast. This storm has an impact on the most densely populated region of the United States, including mega Baltimore, Philadelphia and New York. It is home to 77% of the population and because the consequences of the disaster are the most dramatic.
Norister — it is an active cyclone which moves along the east coast of North America. The name «nor'easter» he received for what the winds are blowing in the coastal area from the north-east.
Norister can occur at any time of year, but most of their frequency of occurrence falls on the cold season, from September to April. These storms usually develop between Georgia and New Jersey within 160 km from the coast and move to the north or north-east.
Noristery tend to reach maximum activity near the New England and Canadian coast. In addition to the heavy snowfall and rain, they bring the storm winds of up to 100 km / h and a powerful surge of water that floods the coastal territory, destroying infrastructure and eroding beaches.
See also: Photos from the United States after Hurricane Nor'easter
Eastern coast North America is a fertile ground for noristerov. In winter, the polar jet stream brings cold Arctic air in the south-east across the plains of Canada and the United States, where it meets the warm air from the Gulf of Mexico, which, in turn, in obedience to the other branch of the jet stream is shifted to the north-east
Over the warm waters of the Gulf Stream, this air mass is further warmed and becomes unstable. The temperature difference between the warm air over the water and cold Arctic air over the land is an area where storms originate norister.