Suzanne Matheny v. United States

POSNER, Circuit Judge.

One wintry day, Suzanne Matheny went sledding on a snow-covered sand dune in the Indiana Dunes National Lakeshore, a national park. Her sled struck a rusty pipe that protruded (the record is unclear how far) above the surface of the dune but was concealed by snow. A year earlier a child had had a similar accident in the same area and park rangers had removed a number of protruding pipes but had failed to discover and remove all of them; objects buried in the dunes may be exposed part of the time and concealed part of the time, owing to the shifting of the sand. The pipes…