Winter snow storms can produce snow in any form from the wet, heavy varieties to powder fluff, or icy pellets. They can be brief squalls or major blizzard events, and, in the case of lake effect snow storms, they may produce several feet of snow in a matter of a few hours. All winter snow storms are, however, potentially dangerous.
One of the most dangerous winter snow storms is, of course, the blizzard, a snow storm with winds over 35 mph. These storms, caused by cold fronts converging on warmer moist air, can produce nearly hurricane force winds in some cases, causing property damage, coastal flooding and snow drifts that may cover buildings. Producing white out conditions that may last for several hours to several days, these are the most lethal snow storms, causing deaths due to the extreme cold and the chance of hypothermia, as a result of power outages or becoming stranded outside in the elements.
Even a heavy snowstorm, producing a great deal of snow, but relatively little wind, can be devastating to an area, causing transportation problems and accidents. The accumulation of heavy snow on roof tops, trees, and power lines may cause them to collapse. During periods of continued cold, this deep snow may linger on for several weeks.
Lake effect snow storms are produced by a snow storm moving across open water. Prevalent near the Great Lakes, these storms move over the warmer, moister water, collecting more fuel as they go. Eventually, they deposit their supply of snow on the leeward side of the lake in amounts that may reach two or three feet in a matter of hours.
Nor’easters are winter snow storms that are notorious for being fierce, frigid, and packed with heavy snow. These storms enter the continent from the northeast by blowing in from the ocean. They are best known on the East Coast, where they blow in from the Atlantic, often with hurricane force winds, causing not only heavy snow, but property damage, flooding, and beach erosion.
Winter storms that have encountered atmospheric conditions that are warmer may produce sleet or freezing rain. When ice storms develop, and the temperature on the ground remains below freezing, ice covered trees, roads and power lines can remain locked in ice for some time. This extremely dangerous condition causes power outages, downed trees and utility lines, and hazardous driving.
All snow storms pose potential dangers to people. Frost bite, hypothermia, and accidents are the most common problems associated with extremes in winter. Winter storm warnings are posted to ensure that people know when these events are likely to begin, and to prepare for any eventuality. Those who live in areas where winter snow storms are common, prepare ahead of time by stocking up on food supplies, fuel, and alternative lighting and heating methods.
http://www.nws.noaa.gov/om/brochures/wintstm.htm
http://www.weather.com/encyclopedia/winter/types.html
