New Guatemala City SinkholeThe appearance of a massive sinkhole in Guatemala City (map), Guatemala, on Sunday is thought to have been triggered by tropical storm Agatha, a violent tempest that struck Central America over the weekend. From photographs, the new Guatemala sinkhole appears to be about 60 feet (18 meters) wide and about 300 feet (100 meters) deep, said James Currens, a hydrogeologist at the University of Kentucky—which explains how the sinkhole was reportedly able to swallow an entire three-story building. Sinkholes can form when water-saturated soil and other particles become too heavy and cause the roofs of existing voids in the soil to collapse, Currens said. Another way sinkholes can form is if water enlarges a natural fracture in a limestone bedrock layer. As the crack gets bigger, the topsoil gently slumps and develops into a sinkhole. In either case, the final collapse can be sudden, Currens said. —Ker Than

Photograph courtesy Paulo Raquec