Want to know where—and when—the next major river flood will hit? Just look up, to the satellites.
Conventional estimates of river volume come from rainfall, of course, and from measurement of the water that seeps from soil and groundwater reserves.

But NASA’s GRACE satellites, for Gravity Recovery and Climate Experiment, can pick up changes in the gravity field in a given river basin. The more water in the basin, the higher the gravity signal.

Scientists used GRACE results from 2003 to 2012 to see if they could have predicted the 500-year flooding event in the Missouri River basin in 2011. Preceding the flood were two significant storms, record snow melt, saturated soils and particularly high groundwater.

With GRACE data, the researchers found that they could have predicted the Missouri River floods months before current prediction models. They say that the technique could be used to forecast floods up to 11 months before such events take place in areas where snow melt or groundwater is a significant contribution.

The research was published in the journal Nature Geoscience. [J. T. Reager, B. F. Thomas and J. S. Famiglietti, River basin flood potential inferred using GRACE gravity observations at several months lead time]

Snow melt and major rain storms are predicted to increase with climate change. Which puts a premium on better flood prediction.

—Cynthia Graber

[The above text is a transcript of this podcast.]

[Scientific American is part of Nature Publishing Group.]

[Sound effect credit: Mike Koenig]