Blizzard

A blizzard is a severe snowstorm characterized by strong sustained winds and low visibility, lasting for a prolonged period of time—typically at least three or four hours. A ground blizzard is a weather condition where snow that has already fallen is being blown by wind. Blizzards can have an immense size and usually stretch to hundreds or thousands of kilometres. , Tehran and affected skiers.

A blizzard is a severe snowstorm characterized by strong sustained winds and low visibility, lasting for a prolonged period of time—typically at least three or four hours. A ground blizzard is a weather condition where snow that has already fallen is being blown by wind. Blizzards can have an immense size and usually stretch to hundreds or thousands of kilometres. , Tehran and affected skiers. ==Definition and etymology== In the United States, the National Weather Service defines a blizzard as a severe snow storm characterized by strong winds causing blowing snow that results in low visibilities. The difference between a blizzard and a snowstorm is the strength of the wind, not the amount of snow. To be a blizzard, a snow storm must have sustained winds or frequent gusts that are greater than or equal to with blowing or drifting snow which reduces visibility to or less and must last for a prolonged period of time—typically three hours or more. Environment Canada defines a blizzard as a storm with wind speeds exceeding accompanied by visibility of or less, resulting from snowfall, blowing snow, or a combination of the two. These conditions must persist for a period of at least four hours for the storm to be classified as a blizzard, except north of the arctic tree line, where that threshold is raised to six hours. , Lancashire, England, January 1963 The Australia Bureau of Meteorology describes a blizzard as, "Violent and very cold wind which is laden with snow, some part, at least, of which has been raised from snow covered ground." , Helsinki, Finland, during a brief but intense blizzard on a March evening. While severe cold and large amounts of drifting snow may accompany blizzards, they are not required. Blizzards can bring whiteout conditions, and can paralyze regions for days at a time, particularly where snowfall is unusual or rare. A severe blizzard has winds over , near zero visibility, and temperatures of or lower. In Antarctica, blizzards are associated with winds spilling over the edge of the ice plateau at an average velocity of . Ground blizzard refers to a weather condition where loose snow or ice on the ground is lifted and blown by strong winds. The primary difference between a ground blizzard as opposed to a regular blizzard is that in a ground blizzard no precipitation is produced at the time, but rather all the precipitation is already present in the form of snow or ice at the surface. The Oxford English Dictionary concludes the term blizzard is likely onomatopoeic, derived from the same sense as blow, blast, blister, and bluster; the first recorded use of it for weather dates to 1829, when it was defined as a "violent blow". It achieved its modern definition by 1859, when it was in use in the western United States. The term became common in the press during the harsh winter of 1880–81. ==United States storm systems== in New York City, 2015. . In the United States, storm systems powerful enough to cause blizzards usually form when the jet stream dips far to the south, allowing cold, dry polar air from the north to clash with warm, humid air moving up from the south. When cold, moist air from the Pacific Ocean moves eastward to the Rocky Mountains and the Great Plains, and warmer, moist air moves north from the Gulf of Mexico, all that is needed is a movement of cold polar air moving south to form potential blizzard conditions that may extend from the Texas Panhandle to the Great Lakes and Midwest. A blizzard also may be formed when a cold front and warm front mix together and a blizzard forms at the border line. Another storm system occurs when a cold core low over the Hudson Bay area in Canada is displaced southward over southeastern Canada, the Great Lakes, and New England. When the rapidly moving cold front collides with warmer air coming north from the Gulf of Mexico, strong surface winds, significant cold air advection, and extensive wintry precipitation occur. , on March 1, 2007. Note the unclear horizon near the center. Low pressure systems moving out of the Rocky Mountains onto the Great Plains, a broad expanse of flat land, much of it covered in prairie, steppe and grassland, can cause thunderstorms and rain to the south and heavy snows and strong winds to the north. With few trees or other obstructions to reduce wind and blowing, this part of the country is particularly vulnerable to blizzards with very low temperatures and whiteout conditions. In a true whiteout, there is no visible horizon. People can become lost in their own front yards, when the door is only away, and they would have to feel their way back. Motorists have to stop their cars where they are, as the road is impossible to see. ===Nor'easter blizzards=== A nor'easter is a macro-scale storm that occurs off the New England and Atlantic Canada coastlines. It gets its name from the direction the wind is coming from. The usage of the term in North America comes from the wind associated with many different types of storms, some of which can form in the North Atlantic Ocean and some of which form as far south as the Gulf of Mexico. The term is most often used in the coastal areas of New England and Atlantic Canada. This type of storm has characteristics similar to a hurricane. More specifically, it describes a low-pressure area whose center of rotation is just off the coast and whose leading winds in the left-forward quadrant rotate onto land from the northeast. High storm waves may sink ships at sea and cause coastal flooding and beach erosion. Notable nor'easters include The Great Blizzard of 1888, one of the worst blizzards in U.S. history. It dropped of snow and had sustained winds of more than that produced snowdrifts in excess of . Railroads were shut down and people were confined to their houses for up to a week. It killed 400 people, mostly in New York. ==Historic events== ===1972 Iran blizzard=== The 1972 Iran blizzard, which caused 4,000 reported deaths, was the deadliest blizzard in recorded history. Dropping as much as of snow, it completely covered 200 villages. After a snowfall lasting nearly a week, an area the size of Wisconsin was entirely buried in snow. ===2008 Afghanistan blizzard=== The 2008 Afghanistan blizzard, was a fierce blizzard that struck Afghanistan on 10 January 2008. Temperatures fell to a low of , with up to of snow in the more mountainous regions, killing at least 926 people. The weather also claimed more than 100,000 sheep and goats, and nearly 315,000 cattle died. ===The Snow Winter of 1880–1881=== The winter of 1880–1881 is widely considered the most severe winter ever known in many parts of the United States. The initial blizzard in October 1880 brought snowfalls so deep that two-story homes experienced accumulations, as opposed to drifts, up to their second-floor windows. No one was prepared for deep snow so early in the winter. Farmers from North Dakota to Virginia were caught flat with fields unharvested, what grain that had been harvested unmilled, and their suddenly all-important winter stocks of wood fuel only partially collected. By January train service was almost entirely suspended from the region. Railroads hired scores of men to dig out the tracks but as soon as they had finished shoveling a stretch of line a new storm arrived, burying it again. view card showing "Blasting ice with dynamite from in front of steamer on the ways, by Stanley J. Morrow" ~ A view of Yankton's riverfront after the flood of March 1881. There were no winter thaws and on February 2, 1881, a second massive blizzard struck that lasted for nine days. In towns the streets were filled with solid drifts to the tops of the buildings and tunneling was necessary to move about. Homes and barns were completely covered, compelling farmers to construct fragile tunnels in order to feed their stock. When the snow finally melted in late spring of 1881, huge sections of the plains experienced flooding. Massive ice jams clogged the Missouri River, and when they broke the downstream areas were inundated. Most of the town of Yankton, in what is now South Dakota, was washed away when the river overflowed its banks after the thaw. ===The Storm of the Century=== The Storm of the Century, also known as the Great Blizzard of 1993, was a large cyclonic storm that formed over the Gulf of Mexico on March 12, 1993, and dissipated in the North Atlantic Ocean on March 15. It is unique for its intensity, massive size and wide-reaching effect. At its height, the storm stretched from Canada towards Central America, but its main impact was on the United States and Cuba. The cyclone moved through the Gulf of Mexico, and then through the Eastern United States before moving into Canada. Areas as far south as northern Alabama and Georgia received a dusting of snow and areas such as Birmingham, Alabama, received up to with hurricane-force wind gusts and record low barometric pressures. Between Louisiana and Cuba, hurricane-force winds produced high storm surges across northwestern Florida, which along with scattered tornadoes killed dozens of people. In the United States, the storm was responsible for the loss of electric power to over 10 million customers. It is purported to have been directly experienced by nearly 40 percent of the country's population at that time. A total of 310 people, including 10 from Cuba, perished during this storm. The storm cost $6 to $10 billion in damages. ==List of blizzards== ===North America=== ===Canada=== The Eastern Canadian Blizzard of 1971 – Dumped a foot and a half (45.7 cm) of snow on Montreal and more than elsewhere in the region. The blizzard caused the cancellation of a Montreal Canadiens hockey game for the first time since 1918. Saskatchewan blizzard of 2007 – January 10, 2007, Canada ===United Kingdom=== Great Frost of 1709 Blizzard of January 1881 Winter of 1894–95 in the United Kingdom Winter of 1946–1947 in the United Kingdom Winter of 1962–1963 in the United Kingdom January 1987 Southeast England snowfall Winter of 1990–91 in Western Europe February 2009 Great Britain and Ireland snowfall Winter of 2009–10 in Great Britain and Ireland Winter of 2010–11 in Great Britain and Ireland Early 2012 European cold wave ===Other locations=== 1954 Romanian blizzard 1972 Iran blizzard Winter of 1990–1991 in Western Europe July 2007 Argentine winter storm 2008 Afghanistan blizzard 2008 Chinese winter storms Winter storms of 2009–2010 in East Asia ==See also== Cold wave Lake-effect snow Nor'easter European windstorm Whiteout (weather) Blowing snow advisory Ground blizzard Severe weather terminology (Canada) Snowsquall Blowing snow List of blizzards ==References== ==External links== Digital Snow Museum Photos of historic blizzards and snowstorms. Farmers Almanac List of Worst Blizzards in the United States United States Search and Rescue Task Force: About Blizzards A Historical Review On The Origin and Definition of the Word Blizzard Dr Richard Wild

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