Dust Bowl

 Introduction

The Dust Bowl, or the "dirty thirties", was a period of severe dust storms causing major ecological and agricultural damage to American and Canadian prairie lands from 1930 to 1936 (in some areas until 1940). Severe drought coupled with decades of intensive farming without crop rotation or other techniques to prevent erosion led to this wide-spread disaster.

caption Figure 1: Dust storm in Stratford, Texas. (Source: NASA)

During the drought of the 1930s, with the grasses destroyed, the soil dried, turned to dust, and blew away eastwards and southwards in large dark clouds. At times the clouds blackened the sky, reaching all the way to East Coast cities such as New York and Washington, D.C. Much of the soil ended up deposited in the Atlantic Ocean. The Dust Bowl affected 100,000,000 acres (400,000 km2), centered on the panhandles of Texas and Oklahoma, and adjacent parts of New Mexico, Colorado, and Kansas.

The storms of the Dust Bowl were given names such as Black Blizzard and Black Roller because visibility was reduced to a few feet (around a meter).  Millions of acres (hectares) of farmland became useless, and hundreds of thousands of people were forced to leave their homes.

Geographic characteristics

caption Figure 2: Palmer Drought Severity Index. (Source:  National Drought Mitigation Center)

The Dust Bowl area lies principally west of the 100th meridian on the High Plains, characterized by plains which vary from rolling in the north to flat in the Llano Estacado. Elevation ranges from 2,500 feet (760 m) in the east to 6,000 feet (1,800 m) at the base of the Rocky Mountains. The area is semi-arid, receiving less than 20 inches (510 mm) of rain annually; this rainfall supports the Shortgrass prairie biome originally present in the area. The region is also prone to extended drought, alternating with unusual wetness of equivalent duration. This is illustrated by Figure 2, in which the darkly shaded areas of the map indicate those areas of the United States which experienced severe drought for the greatest percentage of time in the years between 1895 and 1995. During wet years, the rich soil provides bountiful agricultural output, but crops fail during dry years. Furthermore, the region is subject to winds higher than any region except coastal regions.

Agricultural and settlement history

During early European and American exploration of the Great Plains, the region in which the Dust Bowl occurred was thought unsuitable for agriculture; indeed, the region was known as the Great American Desert. The lack of surface water and timber made the region less attractive for pioneer settlement and agriculture. However, following the Civil War, settlement in the area increased, encouraged by the Homestead Act and westward expansion. The Homestead Act was a United States Federal law that gave an applicant freehold title to 160 acres (one quarter section or about 65 hectares)-640 acres (one section or about 260 hectares) of undeveloped land outside of the original 13 colonies. An unusually wet period in the Great Plains (see Figure 3) led settlers and government to believe that "rain follows the plow" and that the climate of the region had changed permanently. The initial agricultural endeavors were primarily cattle ranching with some cultivation; however, a series of harsh winters beginning in 1886, coupled with overgrazing followed by a short drought in 1890, led to an expansion of land under cultivation.

Immigration into the region began again at the beginning of the 20th century. A return of unusually wet weather confirmed the previously held opinion that the "formerly" semi-arid area could support large-scale agriculture. Technological improvements led to increased automation, which allowed for cultivation on an ever greater scale. World War I increased agricultural prices, which also encouraged farmers to drastically increase cultivation. In the Llano Estacado, farmland area doubled between 1900 and 1920, and land under cultivation more than tripled between 1925 and 1930.

Causes

The event's major causes were severe drought, the expansion of agriculture, and inappropriate methods of cultivation, which in turn has been linked to the proliferation of small farms promoted by the Homestead Act (arguments relying on this claim note that larger farms would have instituted the environmental safeguards that were inefficient in the short-term for smaller farms).

Drought

The unusually wet period, which encouraged increased settlement and cultivation in the Great Plains, ended in 1930. This was the year in which an extended and severe drought began. It is now widely accepted by scientists that this drought corresponded with a La Nina episode in the Pacific Ocean, which not only reduced the amount of moisture entering the jet stream but also diverted it south. Hence, the severity of the drought was compounded by the lack of incoming moisture from the west. Typical plant cover, which exists at roughly 60 percent, drops to 20 percent or lower during periods of drought. The drought caused crops to fail, leaving the plowed fields without any plant cover, completely exposed to wind erosion. The fine soil of the Great Plains was easily eroded and carried east by strong continental winds.

caption Figure 3: This drought record for the Arkansas-White-Red Basin, an area within the Dust Bowl region, illustrates not only the severity and duration of the drought of the 1930s, but also the lack and infrequency of severe drought in previous years (a function of the wet and dry cycles which characterize the region), which falsely led early settlers to believe that the region was wet enough to support the agricultural techniques practiced in the eastern US. (Source:  National Drought Mitigation Center)
 

Misuse of land

The Great Plains region was already in a vulnerable state when drought struck in the 1930s, due largely to numerous faulty land management practices. Most settlers of the region were accustomed to the climate of the eastern United States, from where they had migrated. Thus, their farming practices were based on vastly different ecological conditions, and did not translate well to the arid climate of the Midwest. As economic conditions declined in the 1920s, the need to cultivate more farmland increased. Farmers turned to cultivating poorer quality farmlands, which led to soil erosion and nutrient leaching. Soil conservation practices were overlooked in favor of increased productivity in times of economic stress. For example, cotton farmers left fields bare over winter months, when winds in the High Plains are highest, and burned their wheat stubble, which deprived the soil of organic matter and increased exposure to erosion. All of these factors combined to produce a region which was already extremely vulnerable to drought and wind erosion.

Demographic and cultural factors

While the drought which hit the region of the Dust Bowl in the 1930s was not the first of its kind, the demographic and cultural conditions of the time were unprecedented. To begin with, the population of the region grew sevenfold—from 800,000 to 5.6 million—in the decades between 1880 and 1930. Additionally, the drought and subsequent dust storms occurred during the worst economic depression in American history. The economic depression of the 1930s was compounded by the agricultural depression brought on by the Dust Bowl, which contributed to hardships such as bank closures, business losses, and unemployment.

Dust storms

caption Figure 4: A black blizzard in Colorado. (Source:  Wind Erosion Research Unit)

On November 11, 1933, a very strong dust storm stripped topsoil from desiccated South Dakota farmlands in just one of a series of bad dust storms that year. Then, beginning on May 9, 1934, a strong two-day dust storm removed massive amounts of Great Plains topsoil in one of the worst such storms of the Dust Bowl. The dust clouds blew all the way to Chicago where dirt fell like snow. Two days later, the same storm reached cities in the east, such as Buffalo, Boston, New York City, and Washington, D.C. That winter, red snow fell on New England.

On April 14, 1935, known as "Black Sunday", twenty of the worst "Black Blizzards" occurred throughout the Dust Bowl, causing extensive damage and turning the day to night. Witnesses reported that they could not see five feet in front of them at certain points.   

Migration

The devastation, which began as the economic effects of the Great Depression were intensifying, caused an exodus from Texas, Oklahoma, and the surrounding Great Plains, with more than 500,000 Americans left homeless. One storm caused 356 houses to be torn down. Many Americans migrated west looking for work, while many Canadians fled to urban areas such as Toronto. 

The Dust Bowl exodus was the largest migration in American history within a short period of time. The second wave of the Great Migration by African Americans from the South to the North was larger, involving more than 5 million people, but it took place over decades, from 1940-1970. By 1940, 2.5 million people had moved out of the Plains states; of those, 200,000 moved to California. With their land barren and homes seized in foreclosure, many farm families were forced to leave. Migrants left farms in Oklahoma, Kansas, Texas, and New Mexico, but all were generally referred to as "Okies". The plight of Dust Bowl migrants became widely known from the novel The Grapes of Wrath by John Steinbeck.

Government response

During President Franklin D. Roosevelt's first 100 days in 1933, governmental programs designed to restore the ecological balance of the nation were implemented. In the following years, the New Deal government enforced further reform plans. The Resettlement Administration (RA), which eventually became the Farm Security Administration (FSA), stressed "rural rehabilitation" efforts to improve the lifestyle of sharecroppers, tenants, and very poor landowning farmers, and a program to purchase submarginal land owned by poor farmers and resettle them in group farms on land more suitable for efficient farming. The Soil Conservation Service (SCS) encouraged cultivation techniques which would prevent further soil erosion. Finally, the Agricultural Adjustment Administration (AAA) restricted production by paying farmers to reduce crop area. The farmers were paid subsidies by the federal government for leaving some of their fields unused.

 References

 

Glossary

Citation

Buonanduci, M. (2009). Dust Bowl. Retrieved from http://www.eoearth.org/view/article/151818

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