Dora Linda Nishihara, 68, was driving in San Antonio one dark evening in early December when she suddenly disappeared from sight. Later, her car, with her body inside, was found at the bottom of a 12-foot-deep, water-filled sinkhole that had swallowed the road ahead of her. Two days later, a school bus driver in Brooklyn, New York, ran into an 8-foot-wide crater on his route. Just last week, massive holes opened up in New York City's lower Manhattan, suburban Atlanta, and San Francisco. Sinkholes are not a new phenomenon in the United States, especially in a half dozen states where the geology makes them more likely. But a recent spate of huge, sudden-appearing caverns is prompting alarm because they're happening in places where they shouldn't, and now seem to be proliferating nationwide.
The usual cause: crumbling water, drain, and sewer pipes, often neglected by cities with budget problems. No government agency keeps track of sinkholes from man-made causes. But scientists who study natural sinkholes say the caverns from infrastructure failures are becoming a bigger problem. From early December through April, according to a review by the AP of media coverage, 39 significant sinkholes related to failing infrastructure— a rate of about one every four days— struck across the country in places as varied as Chicago; Los Angeles; Hoboken, New Jersey; Sioux City, Iowa; and Seattle. One person was killed and four were injured in the incidents, which also prompted extensive evacuations and disruption of utilities. Some experts are calling now for a national study to assess the risk and potential remedies, which could involve high costs for many jurisdictions. (Read more sinkhole stories.)