Residents in Chicago's south side had a scare after a 40-foot-wide sinkhole opened up at 96th and Houston this morning. Two cars were immediately consumed by the void and a third fell in shortly after firefighters arrived on the scene, according to The Huffington Post. One pedestrian also fell in and suffered mild injuries. Chicago has seen over five inches of rain fall in less than 24 hours, saturating the ground and causing extensive flooding.
Sinkholes typically form in areas with easily dissolved rocks underground, such as limestone. As groundwater erodes these rocks, voids form in the soil, and heavy rains can cause those voids to implode, bringing the surface down at the same time. The Jeffrey Manor neighborhood, where this sinkhole occurred, is just 15 miles from the Thornton Limestone Quarry in Thornton, IL. You can watch a local news report on the incident below for more information.