Flash floods occur suddenly and due to quickly rising waters caused by heavy rains over a short time period. Aside from making everything soggy, they can be powerful enough to uproot trees and sweep away bridges.
How to stay safe: Monitor local media during heavy rains. In the event of a flash-flood watch, "you want to be prepared to evacuate at a moment's notice," says Judge. A flash-flood warning means flooding is happening or will soon occur in your area and you should seek higher ground immediately.
No matter what: Don’t drive or walk through rising water. "Most cars can be swept away by less than two feet of moving water," says Judge. In fact, a high percentage of flood deaths happen in vehicles. Instead, turn around and drive to higher ground, or leave the car and run to higher ground if the road is blocked.