What made the rain in Hurricane Harvey so extreme?

By Russ Schumacher, Associate Professor of Atmospheric Science, Colorado State University. The rainfall from Harvey has now exceeded the amount from the previous record-bearer, Tropical Storm Amelia in 1978. AP Photo/Charlie Riedel Fifty inches of rain. Nine trillion gallons of water. The Gulf Coast of Texas, and especially the Houston metropolitan area, has been inundated by…