A combination of heavy rain and large snow melt has caused devastating flooding in parts of the U.S. this spring. With water levels in some areas along the Mississippi river reaching near record heights.
This new map, based on data gathered by NASA’s Tropical Rainfall Measuring Mission (TRMM), compares rainfall from April May 4, 2011 with the average for the same period over the previous ten years. Anomalies above and below average are displayed in mm per day
Interpreting the results, NASA suggests La Niña as a possible reason for this above normal precipitation:
Despite the fact that the current La Niña appears to be winding down, its effects in the atmosphere can persist for a while…La Niña’s are conducive for above-normal rainfall from East Texas and northern Louisiana up through Arkansas and the Tennessee and Ohio Valleys with below-normal rainfall across Texas, southern Louisiana and Florida.