Major flooding is forecast for one-third of the U.S. in the next few weeks—and truckloads of sandbags are headed to cities across the Midwest. The risk extends from West Texas through the South and up to the southern part of New England. Central Texas, with its thin, rocky soil, is particularly in danger: Austin has already weathered 3 more inches of rain than it usually gets in a year. El Niño, expected to continue through the spring, has left many areas soggy after a snowy winter. This year’s snowpack ranks among the Top 10 since the 1940s. "We are looking at potentially historic flooding," a National Oceanic and Atmospheric Administration official said. "It's a terrible case of déjà vu, but this time the flooding will likely be more widespread."