A mother and her two children were reported killed when a flash flood hit Pittsburgh on Friday. Authorities in Pittsburgh said heavy rain caused the flash flood which submerged cars in a nine-feet deep flood water. In the initial police investigation, the victims died after their vehicle was pinned against a tree on Washington Boulevard and they were unable to escape.
Michael Huss, the city’s public safety director revealed the water was more than nine feet deep in some areas along the road, which is near the banks of the Allegheny River. Huss said at the moment some 18 cars were stranded in the flooding and 11 people had to be rescued. A flash flood is a rapid flooding of geomorphic low-lying areas—washes, rivers, dry lakes and basins.
It may be caused by heavy rain associated with a storm, hurricane, or tropical storm or melt-water from ice or snow flowing over ice sheets or snowfields. Flash floods may occur after the collapse of a natural ice or debris dam, or a human structure such as a man-made dam, as occurred before the Johnstown Flood of 1889. Flash floods are distinguished from a regular flood by a timescale less than six hours. The temporary availability of water is often utilized by foliage with rapid germination and short growth cycle, and by specially adapted animal life.