Climate Fact: Southern U.S. Drought Occurrence Linked to SST Variability: Causes of Northern Droughts Less Clear
Better drought prediction systems could potentially save billions of dollars. Current prediction systems largely rely on observations of the circumstances surrounding past droughts to understand the factors that led to drying. New research reveals that:
- Drought in the southern Great Plains states, such as the 1946-1956 drought, can be largely explained by persistently cool conditions in the eastern tropical Pacific.
- Drought in the northern Great Plains states, such as the 1930′s “Dust Bowl,” was likely caused by serendipitous atmospheric variability (i.e. a variety of atmospheric factors came together with the result being the Dust Bowl) and agricultural practices. The initial atmospherically forced drying resulted in dust storms that reinforced these dry conditions.
Predicting drought may be more difficult in the northern Great Plains than southern Great Plains, as the causes of drought in the former region are much more complex.
Seasons: Winter, Spring, Summer, Fall
Source: Hoerling, M et al. “Distinct causes for two principal U.S. droughts of the 20th century.” Geophysical Research Letters 36 (2009): L19708.
