<human>:  What caused the dustbowl of the 1930s?
<bot>: The Dust Bowl of the 1930s was caused by a combination of extreme weather conditions and unsustainable farming practices. A severe drought hitting the Great Plains region was the primary cause of the Dust Bowl, combined with decades of extensive deep plowing and overgrazing of grasslands by livestock, which weakened the soil and left it vulnerable to erosion and wind blowing.