Current potential flash drought areas in South America
Fig. 1: Identifying the current risk zones for flash drought in South America. During summertime when heat is most intense the areas identified are susceptible to flash drought if a period of extreme heat and dry weather occurs due to the long-term and short-term rainfall deficits which contribute to both shallow and deep soil moisture deficits.
Research produced by the Auburn University School of Forestry and Wildlife Sciences updated the long-known concept of increased drought risk caused by the combination of long-term rainfall deficits often revealed in lowering deep soil moisture AND short-term rainfall deficits commonly depicted with Palmer Drought Severity Index (PDSI). The research identifies the combination of each regime in a specific region increases the risk of flash drought during the warm season if a relatively short period of anomalous heat and dry weather occurs. Using this methodology and identifying the JAN-SEP 2019 (Fig. 2), JUL-SEP 2019 (Fig. 3) and October 2019 (Fig. 4) rainfall deficits areas of potential flash drought can be projected. They are Mato Grosso Do Sul in southwest Brazil and southern Buenos Aires in Argentina. Mato Grosso Do Sul is located in the central Brazil soybean crop area while southern Buenos Aires is where soybean and wheat crop areas are located in Argentina.
Fig. 2-4: The 9-month, 3-month and 30-day precipitation anomalies across South America.