The Dust Bowl was a severe drought that hit the U.S. Midwest in the 1930s. It was caused by irregular fluctuations in ocean temperatures, dry climates and poor farming techniques. It was characterized by massive dust storms that contributed to the harsh and dry climate.
Cooler than normal temperatures over the Pacific Ocean and warmer temperatures over the Atlantic created the dry climate necessary for the drought to occur. These temperature fluctuations caused the jet stream, which typically carried moist air from the Gulf of Mexico, to become drier and change direction, leading to decreased rainfall over the Midwest.
Poor farming practices and the unusually dry climate caused the surface soil in the Midwest to be eroded by wind, leading to highly damaging dust storms. Farmers at that time removed the natural grasses that could withstand harsh temperatures and helped keep the soil in place to grow crops such as corn. These crops degraded the quality of the soil over time, and the topsoil began to blow away during storms. Overgrazing of cattle and sheep herds depleted plant cover in the fields, which also contributed to the wind erosion. After several years of the Dust Bowl, farmers began to implement more environmentally-conscious techniques in an attempt to reduce the effects of their previous practices.