The flow through Midwest rivers generally peaks in April as snowmelt from the Appalachian Plateau and northern States combines with the copious precipitation of early spring. In addition, the leafing of trees and shrubs is limited during that season, transpiration is reduced and runoff increases through the numerous tributaries.
This year, torrential rains were superimposed on this natural cycle as a stationary front brought a seemingly endless train of storms across the region. Beginning in mid April and persisting for several weeks, the rains fell on saturated ground and flash floods were common from eastern Oklahoma and Kansas to the Great Lakes and Appalachians. Eventually, all of this water drained into the Ohio and Mississippi Rivers, producing an inland surge that is now cresting at Memphis; over the next few weeks this surge will move further south, flooding the river towns of Louisiana and Mississippi.
Having channelized the rivers, destroyed the wetlands and developed the floodplains, we pretend to have the capacity to control nature's drainage system; yet, every year, in some region of the country, we find that this self-confidence is a delusion. This year, the lesson has been especially harsh.
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