Blizzards

Introduction

Blizzards are extreme snow events that occur when high winds whip snow cover and falling snow into suspension in the air for prolonged periods, causing deep drifts, extreme wind chill, and severely reduced visibility. Blizzards typically occur from late fall to early spring at high latitudes and altitudes, and less frequently in temperate regions.

The effect of human-caused climate change on blizzards, which tend to be associated with cold, low pressure zones in storm systems called cyclones, has not been thoroughly studied and will likely vary from region to region. However, as with other types of snowstorms, blizzards are, in general, predicted to occur less frequently over the course of the century. This decrease in total number of storms will likely be accompanied by an increase in the intensity of blizzards that do occur, due to elevated levels of humidity as temperatures climb, resulting in more precipitation and more violent storms.

Historical Background and Scientific Foundations

The occurrence of blizzards has varied widely over the past 50 years in different locations. On the prairies of western Canada, for example, the number of blizzards decreased between 1953 and 1997. In the contiguous United States,

the number of blizzards has increased slightly since the 1950s, while the overall number of severe, damaging snowstorms has shown no significant trend in either direction. But the incidence of more extreme precipitation events like severe blizzards, as well as above normal temperatures and drought, rose considerably in different parts of the United States between 1980 and 1994. Meanwhile, subsistence reindeer herders in eastern Russia have also reported anecdotal increases in intense snowstorms and other extreme weather events.

As temperatures warm due to increased greenhouse-gas emissions over the coming century, storms may become more infrequent and more extreme. General circulation computer models show that extra-tropical cyclones, which tend to spawn severe snowstorms like blizzards in the wintertime at mid and high latitudes, will likely decrease. Rising temperatures will also mean that more precipitation falls as rain. These models also predict an increase in cyclone intensity, which may, in turn, result in an increase in the intensity of accompanying snowstorms. Climate models that factor in greater atmospheric concentrations of carbon dioxide and warming tend to predict the greatest increases in cyclone intensity.

Impacts and Issues

Blizzards can pose significant impediments to travel by ground and air, hamper economic activity, knock out electricity, damage structures, and wipe out livestock, as well as cause human injuries and death through vehicle crashes and exposure. But big storms can also boost soil moisture and water supplies, and be an economic boon to winter recreation industries like ski resorts.

WORDS TO KNOW

: A quantitative way of representing the interactions of the atmosphere, oceans, land surface, and ice. Models can range from relatively simple to quite comprehensive.

: The angular distance north or south of Earth's equator measured in degrees.

: Moisture that falls from clouds. Although clouds appear to float in the sky, they are always falling, the water droplets slowly being pulled down by gravity. Because the water droplets are so small and light, it can take 21 days to fall 1,000 ft (305 m) and wind currents can easily interrupt their descent. Liquid water falls as rain or drizzle. All raindrops form around particles of salt or dust. (Some of this dust comes from tiny meteorites and even the tails of comets.) Water or ice droplets stick to these particles, then the drops attract more water and continue getting bigger until they are large enough to fall out of the cloud. Drizzle drops are smaller than raindrops. In many clouds, raindrops actually begin as tiny ice crystals that form when part or all of a cloud is below freezing. As the ice crystals fall inside the cloud, they may collide with water droplets that freeze onto them. The ice crystals continue to grow larger, until large enough to fall from the cloud. They pass through warm air, melt, and fall as raindrops.

A decrease in the overall frequency of severe snowstorms may benefit certain industries, but an increase in the intensity of storms that do occur will increase the danger and damage resulting from individual storms. Meanwhile, less overall snowfall from fewer storms may jeopardize ecosystems that rely on snow for freshwater, such as those in big mountain ranges like the Himalayas or the Rocky Mountains.

See Also Anthropogenic Change; Catastrophism; Extreme Weather; General Circulation Model (GCM); Lake Effect Snows; Melting; Rainfall; Tourism and Recreation.

BIBLIOGRAPHY

Books

Weart, Spencer. The Discovery of Global Warming. Cambridge, MA: Harvard University Press, 2004.

Periodicals

Changnon, Stanley A., and David Changnon. “A Spatial and Temporal Analysis of Damaging Snowstorms in the United States.” Natural Hazards 37 (March 2006): 373–389.

Easterling, D. R., et al. “Observed Variability and Trends in Extreme Climate Events: A Brief Review.” Bulletin of the American Meteorological Society 81 (March 2000): 417–425.

Lambert, Steven J. “The Effect of Enhanced Greenhouse Warming on Winter Cyclone Frequencies and Strengths.” Journal of Climate 8 (May 1995): 1447–1452.

Lambert, Steven J., and John C. Fife. “Changes in Winter Cyclone Frequencies and Strengths Simulated in Enhanced Greenhouse Warming Experiments: Results from the Models Participating in the IPCC Diagnostic Exercise.” Climate Dynamics 26 (June 2006):713–728.

Lawson, Bevan D. “Trends in Blizzards in Selected Locations on the Canadian Prairies.” Natural Hazards 29 (June 2003): 123–138.

McCabe, Gregory J., et al. “Trends in Northern Hemisphere Surface Cyclone Frequency and Intensity.” Journal of Climate 14 (June 2001): 2763–2768.

Schwartz, Robert M., and Thomas W. Schmidlin. “Climatology of Blizzards in the Conterminous United States, 1959–2000.” Journal of Climate 15 (July 2002): 1765–1772.

Stevens, William K. “Blame Global Warming for the Blizzard.” The New York Times (January 14, 1996).

Web Sites

“Witnessing Climate Change in Russia's Far East.” WWF, May 10, 2006. < http://www.panda.org/news_facts/newsroom/features/index.cfm?uNewsID=67580> (accessed November 18, 2007).

Sarah Gilman

BLIZZARDS

BLIZZARDS are defined by the National Weather Service as winter storms with sustained or gusting winds of 35 mph that produce blowing or drifting snow that reduces visibility to one-quarter mile or less for over three hours. While this is the technical definition of the word, for most people any sustained snowstorm accompanied by fierce winds is considered a blizzard. Blizzards are often, but not always, accompanied by extremely cold temperatures. They are most common in the Great Plains, the Great Lakes states, and the northeastern states along the coast, and less common in the Pacific Northwest.

The earliest European settlers in the colonies were stunned by the ferocity of North American blizzards. In 1717 a blizzard hit the eastern seaboard and was known as the "Great Snow" for more than a century. During this storm three to four feet of snow fell and harsh winds whipped it into twenty-five-foot drifts.

By the nineteenth century settlement had stretched westward, and settlers there were exposed to the howling winds and heavy snows of the prairie and plains areas. Railroads were frequently stalled by heavy snows. Food and fuel shortages could develop over time if a blizzard persisted for days on end. Fires were also a hazard in blizzards as stoves were overworked and water lines froze, preventing effective fire suppression. Telegraph, electric, and phone lines could be toppled. And the new suspension bridges could collapse under the heavy load of snow and ice.

Major blizzards racked the nation during the nineteenth century. In October of 1846 a blizzard struck northern California. Over eight days, heavy snows resulted in forty-foot drifts over Truckee Pass. The Donner Party of eighty-seven was trapped on the mountain, and when spring finally came in April of that year only forty-seven made their way back down. Cannibalism was reported here and elsewhere during blizzards in isolated western regions. In 1873 a major blizzard struck the northern Great Plains, leaving at least seventy people dead and paralyzing the railroad system for much of the winter.

In January of 1888 a blizzard struck the Great Plains, with deep snow and rapidly falling temperatures. The thermometer dropped sixty degrees in eighteen hours. Many of the 200 dead were children trying to make their way home from school. Later that year came the "Blizzard of '88." This storm still warrants inclusion in many history books for its sheer size and ferocity. From the Chesapeake Bay to Nantucket nearly 200 ships were damaged or destroyed. Then, from 10 to 14 March, the eastern seaboard was pummeled. From two to four feet of snow fell over three days across much of the region. Freezing temperatures were accompanied by wind gusts of over 70 mph across New York City. The snow drifted more than twenty feet deep, covering vehicles and even the first floors of some New York City structures. People in the city were trapped in elevated cars, stores, trains, and offices. In Connecticut and Massachusetts, forty to fifty inches of snow fell and formed drifts up to fifty feet deep. Entire houses and trains were buried. At the end of the storm more than 400 people had died.

By the twentieth century new technologies helped people deal with the consequences of blizzards. Massive plows could be attached to locomotives or trucks. Telegraphs and phones could be used to report approaching blizzard conditions. And by later in the century, sophisticated weather tracking and warning systems were in place. In Washington, D.C., from 27 to 29 January 1922, a winter storm buffeted the city, leaving nearly two feet of snow. It became known as the "Knickerbocker Storm" because the roof of the Knickerbocker Theater collapsed, killing nearly 100 inside. In 1941, March started out warm in the upper Midwest, and duck hunters took to the lakes when the season opened. But on 15 March a sudden blizzard whipped up and more than seventy died in the Dakotas, Minnesota, Wisconsin, and Michigan. A famous blizzard struck Chicago in 1967 when a series of strong storms struck at the western edge of Lake Michigan. It began on 26 January, and by the next day two feet of snow covered the city. It took two weeks to clear the snow; during that time sixty people died and the city experienced heavy looting.

In the late twentieth century two major storm periods racked the nation. The "Superstorm of 1993" (some called it the "Blizzard of the Century") arrived in March of that year involving nearly two-thirds of the entire nation and setting snowfall records across the eastern seaboard. Blizzard conditions existed from Alabama to Massachusetts, where some termed the storm a "white hurricane." To the west lay a vast track of thunderstorms, tornadoes, and floods. At least ninety-two died in the series of storms. In 1996 came another "Blizzard of the Century," blasting the snowfall records set in 1993. The storm came in three major parts, again affecting nearly two-thirds of the continental United States. It began in the southeast, striking from 6 to 8 January. As it moved north, it left more than four feet of snow in places like Virginia, a record snowfall. Nearly three feet of snow fell in Pennsylvania and two feet in parts of New York and New Jersey. Nine states were virtually paralyzed, and more than 100 people died. A week later, 11–13 January, another storm rocked the northeast. The following week, 17–18 January, a major blizzard struck the central and northern plains.

Yet another season of major winter storms and blizzards arrived the next November, beginning with massive ice storms. Blizzards struck some areas of the Great Plains and Great Lakes two times a week in a repeated pattern that left record snow amounts of two to three feet per blizzard. Winter temperatures reached minus eighty degrees with wind chills. Total snowfall in some Great Plains and Great Lakes areas exceeded 100 inches. The fall and

winter storms left a season of disastrous flooding from the Red River of the north to parts of the Upper Mississippi.

BIBLIOGRAPHY

Cable, Mary. The Blizzard of '88. New York: Atheneum, 1988.

PollyFry

See alsoDisasters ; Weather Service, National .

cold wave The conditions associated with air of continental polar origin, often dominated by an anticyclone behind a cold front, that moves south into central and eastern parts of the USA. Cold waves are defined as a fall of 11°C or more to a minimum base (−18°C in northern, central, and north-eastern regions) within a 24-hour period. In southern states (Florida, California, and the Gulf Coast) the minimum fall is 9°C and the base minimum 0°C.

cold wave The conditions associated with air of continental polar origin, often dominated by an anticyclone behind a cold front, that moves south into central and eastern parts of the USA. Cold waves are defined as a fall of 11°C or more to a minimum base (−18°C in northern, central, and northeastern regions) within a 24-hour period. In southern states (Florida, California, and the Gulf Coast) the minimum fall is 9°C and the base minimum 0°C.

snow·storm / ˈsnōˌstôrm/ • n. a heavy fall of snow, esp. with a high wind. ∎ fig. a shower or large quantity of something: it swam away in a flurry of wings and flippers, raising a snowstorm of foam. ∎ chiefly British term for snow globe.