DES MOINES, Iowa (AP) — The derecho that caused massive damage in Iowa this past week could offer lessons for forecasters and the public. The unusual storm packed the power of a category 3 hurricane but lacked the days of warning a typical hurricane offers. At least three people in Iowa and one in Indiana were killed. Forecasters had predicted thunderstorms and in some communities tornado sirens sounded before the winds began. But many people were caught off guard.

The National Weather Service and the National Oceanic and Atmospheric Administration are working on tools that would assist forecasters in making predictions that consider a range of possibilities.