Many accidents and natural disasters have done serious environmental damage to the United States. Some of the most famous events include the 1989 Exxon Valdez oil spill, the 2008 coal ash spill in Tennessee, and the Love Canal toxic dump disaster that came to light in the 1970s. But despite their tragic consequences, none of these events come close to being the worst environmental disaster in the United States. That grave title belongs to the 1930s Dust Bowl, created by the drought, erosion, and dust storms (or "black blizzards") of the so-called Dirty Thirties. It was the most damaging and prolonged environmental disaster in American history.

The dust storms started at about the same time that the Great Depression really began to grip the country, and it continued to sweep across the Southern Plains—western Kansas, eastern Colorado, New Mexico, and the panhandle regions of Texas and Oklahoma—until the late 1930s. In some areas, the storms didn't relent until 1940.

Decades later, the land is still not completely restored. Once-thriving farms are still abandoned, and new dangers are again putting the Great Plains in serious jeopardy.

The Dust Bowl Causes and Effects

In the summer of 1931, rain stopped falling and a drought that would last for most of the decade descended on the region.

And how did the Dust Bowl affect farmers? Crops withered and died. Farmers who had plowed under the native prairie grass that held soil in place saw tons of topsoil—which had taken thousands of years to accumulate—rise into the air and blow away in minutes. On the Southern Plains, the sky turned lethal. Livestock went blind and suffocated, their stomachs full of fine sand. Farmers, unable to see through the blowing sand, tied themselves to guide ropes to make the walk from their houses to their barns.

It didn't stop there; the Dust Bowl affected all people. Families wore respiratory masks handed out by Red Cross workers, cleaned their homes each morning with shovels and brooms, and draped wet sheets over doors and windows to help filter out the dust. Still, children and adults inhaled sand, coughed up dirt, and died of a new epidemic called "dust pneumonia."

Frequency and Severity of Storms

The weather got worse long before it got better. In 1932, the weather bureau reported 14 dust storms. In 1933, the number of dust storms climbed to 38, nearly three times as many as the year before.

At its worst, the Dust Bowl covered about 100 million acres in the Southern Plains, an area roughly the size of Pennsylvania. Dust storms also swept across the northern prairies of the United States and Canada, but the damage there couldn't compare to the devastation farther south.

Some of the worst storms blanketed the nation with dust from the Great Plains. A storm in May 1934 deposited 12 million tons of dust in Chicago and dropped layers of fine brown dust on the streets and parks of New York and Washington, D.C. Even ships at sea, 300 miles off the Atlantic coast, were left coated with dust.

Black Sunday

The worst dust storm of all hit on April 14, 1935—a day that became known as "Black Sunday." Tim Egan, a New York Times reporter and best-selling author who wrote a book about the Dust Bowl called "The Worst Hard Time," described that day as one of biblical horror:

"The storm carried twice as much dirt as was dug out of the earth to create the Panama Canal. The canal took seven years to dig; the storm lasted a single afternoon. More than 300,000 tons of Great Plains topsoil was airborne that day."

Disaster Gives Way to Hope

More than a quarter-million people became environmental refugees—they fled the Dust Bowl during the 1930s because they no longer had the reason or courage to stay. Three times that number remained on the land, however, and continued to battle the dust and to search the sky for signs of rain.

In 1936, the people got their first glimmer of hope. Hugh Bennett, an agricultural expert, persuaded Congress to finance a federal program to pay farmers to use new farming techniques that would conserve topsoil and gradually restore the land. By 1937, the Soil Conservation Service had been established, and by the following year, soil loss had been reduced by 65%. Nevertheless, the drought continued until the autumn of 1939, when rains finally returned to the parched and damaged prairie.

In his epilogue to "The Worst Hard Time," Egan writes:

"The high plains never fully recovered from the Dust Bowl. The land came through the 1930s deeply scarred and forever changed, but in places, it healed...After more than 65 years, some of the land is still sterile and drifting. But in the heart of the old Dust Bowl now are three national grasslands run by the Forest Service. The land is green in the spring and burns in the summer, as it did in the past, and antelope come through and graze, wandering among replanted buffalo grass and the old footings of farmsteads long abandoned."

Looking Ahead: Present and Future Dangers

In the 21st century, there are new dangers facing the Southern Plains. Agribusiness is draining the Ogallala Aquifer, the United States' largest source of groundwater, which stretches from South Dakota to Texas and supplies about 30% of the nation's irrigation water. Agribusiness is pumping water from the aquifer eight times faster than rain and other natural forces can refill it.

Between 2013 and 2015, the aquifer lost 10.7 million acre-feet of storage. At that rate, it will be completely dry within a century.

Ironically, the Ogallala Aquifer is not being depleted to feed American families or to support the kind of small farmers who hung on through the Great Depression and the Dust Bowl years. Instead, the agricultural subsidies that began as part of the New Deal to help farm families stay on the land are now being given to corporate farms that are growing crops to be sold overseas. In 2003, U.S. cotton growers received $3 billion in federal subsidies to grow fiber that would ultimately be shipped to China and made into cheap clothing to be sold in American stores.

If the water runs out, there won't be any for the cotton or the inexpensive clothing, and the Great Plains could be the site of yet another environmental disaster.