The extreme events of winter 1995-96 were associated with normal features of the climate.

The flow of air in the upper troposphere (7-12 km above the surface of the earth), whose core is called the jet stream, was experiencing large undulations during the December 1995 and January 1996 period which were within normal bounds for what meteorologists call planetary waves in the winter climate. Such undulations of the jet stream are ideal for conversion of energy from the core flow to smaller scale waves which manifest themselves at the earth's surface as storms. A large pool of cold air near the surface was in place several days before the blizzard. And there was an abundance of moisture in the air (available for conversion to precipitation) from the warm water of the Gulf of Mexico during the early part of the storm, and, later, from the warm waters of the Gulf Stream in the Atlantic Ocean. All these characteristics of the weather over North America during the period have been observed many times before. Their confluence in space and conjunction in time were unusual, and resulted in snow accumulations such as have been observed only a few times this century. Likewise, the cold air outbreak that followed the east coast blizzard and brought record cold temperatures to most of the middle and eastern portions of the country as well as the moisture laden storms that dumped record rain amounts on the Pacific Northwest were associated with large excursions of the jet stream from a zonal (east-west) flow.

The 500 mb height map (reproduced from the January 1996 Climate Diagnostics Bulletin of the Climate Prediction Center, National Centers for Enviromental Prediction, National Oceanic and Atmospheric Administration) shows the upper tropospheric flow pattern observed during January 1996 (solid contours) and its deviation from the climatic normal flow (colored shading). The large undulations of the contour lines clearly show that the upper troposphere was experiencing energetic planetary scale waves during the month and that these waves were of larger amplitude than the climatic normal (since the positive departures from normal were located in roughly the same place as the observed ridges and negative departures were correlated with troughs).