"Houses were shut
tight, and cloth wedged around doors and windows, but the dust came in so
thinly that it could not be seen in the air, and it settled like pollen on the
chairs and tables, on the dishes." - John Steinbeck, The Grapes of Wrath
There have been many comparisons between
2012's growing drought and the 1930's
Dust Bowl. Both happened in a time of economic downturn. Both
are accompanied by stunning images of dry, withered land. Both have sparked
deep concerns about the state of the environment and whether our land and
lifestyles are sustainable.
However, there are huge differences.
"In terms of percent area of country
affected by drought (as measured by the Palmer Drought Index), the 1930's Dust
Bowl decade is the worst drought on record by spatial area,"
says Richard
Heim, a meteorologist and drought expert with NOAA's National Climactic Data
Center.
The Dust Bowl was not solely caused by
drought. It was a complicated conflux of three factors that combined to
create a natural disaster of epic proportions: weather, poor farming practices,
and lack of environmental understanding. In essence, the Dust Bowl was a perfect storm of a natural disaster.
We're going to take you back in history to the Dust Bowl, the worst drought in
recorded U.S. history, and explain what happened meteorologically,
agriculturally and culturally.
The Dust Bowl term is used to describe the
massive dust storms that formed in the Plains during the 1930s. Unlike the dust
storms that form in Arizona or New Mexico that last only a few hours, these
storms lasted days and affected dozens of states.
What: A period of severe drought and dust storms.
Where: Plains states though Texas and Oklahoma bore the brunt
of the damage.
When: 1930s,
particularly 1934 and 1936.
Impact: Major ecological and agricultural damage to American
prairie lands
The "why" of the story is the
hardest to explain because it's a combination of weather, environmental and
educational factors. We start with the weather angle.
"In July of 1934, 80 percent of the
country was affected by drought," says Heim. "At its peak the drought
went from the West Coast, to the Great Plains, to the Midwest and the East
Coast."
Desertification was an issue during the Dust
Bowl years. A desert is defined as an area that receives less than 10 inches of
rain a year. Some cities went several years in a row with less than 10 inches
of precipitation, thereby becoming, by definition, a desert.
The area is known as semi-arid and is
naturally prone to drought and high winds. In fact, early settlers referred to
it as the "Great American Desert."
For decades, farmers worked the same plots of
land and didn't use any of the techniques we now know will help keep farming
from depleting the resources of land: crop rotation, fallow fields, cover crops
and techniques to prevent wind erosion.
Massive dust storms, referred to as
"black blizzards," enveloped Plains towns. The dust storms lasted for
days, and sometimes the dust reached East Coast cities like New York and
Washington D.C.
The region's natural defenses are critical to
its survival during drought. That leads us to the next contributing factor for
the Dust Bowl: lack of environmental understanding.
Farmers plowed deep into the virgin topsoil
of the Great Plains displacing the natural grasses. The native grasses of the
Plains were deep-rooted and kept the high winds from blowing away soil. They
also trapped moisture.
"Farmers basically plowed up the land,
plant the crops, let them grow," reports NOAA drought expert Heim.
"So when the rains did not come there
was no vegetative coverage to hold the land down. The wind would pick up the
dirt and create these massive dust bowls."
In addition, cotton farmers left fields bare
during the winter or burned what was left in the field to control weeds. That
stripped the land of remaining nutrients and eliminated surface vegetation,
which would help keep moisture in place and keep the soil from blowing away in
high winds.
While we can never stop a drought or any
other weather event, we have learned a lot since the Dust Bowl.
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