Wednesday, May 1, 2013

Droughts and Floods

It took a flooding event to rescue the Mississippi River from the abnormally low water levels of the past year. Actually, one flood was not enough. The initial heavy rain fell over a relatively narrow band near the river, and will have drained away in a month. But there have been more areas of flooding since, ensuring that the Mississippi River will have at least enough water to get through the summer.

This pattern of drought interrupted by floods is familiar in most deserts around the world. It is covering more areas now as patterns of precipitation change, and pavement and deforestation reduce the land’s ability to hold water between storms.