The Dallas area is still reeling from record-breaking downpours that triggered flash floods across northeastern Texas last week. The event swamped houses, submerged vehicles and prompted hundreds of emergency rescues. At least one death has been reported so far. The sheer volume of rain was stunning, with some locations receiving more than a foot. But the deluge was all the more surprising because Dallas has been choked by severe drought for months. It’s a phenomenon often referred to by scientists as “weather whiplash.” And Texas isn’t the only place it’s happened this summer. Monsoon rains triggered flash floods in Arizona and New Mexico in the past week, even as the Southwest continues to suffer under a decades long drought.