The Bucks tragedy occurred in a hazardous flood zone

The Delaware River has long been a source of disruptive flooding along riverside communities such as Upper Makefield Township; Yardley; and, of course, Philadelphia.

But what happened Saturday night in Upper Makefield when at least five people perished after they were swept away, occurred a good mile from the river along Hough’s Creek.

One thing that contributed to the ferocity of the flooding was the narrowness of the creek, officials said. The narrower the stream, the more prone it tends to be to flash-flooding, said Seann Reed, hydrologist with the government’s Middle Atlantic River Forecast Center. It simply couldn’t hold the incredible volume of water falling from the sky and running off from paved surfaces in a compressed period.

That section of Upper Makefield Township is in a special flood hazard area based on Federal Emergency Management Agency flood maps. Here’s a look at the flood risk throughout the Philadelphia region.