Swollen soil occurs when dry ground tightens up and expands after it receives moisture. It's considered the most severe geological hazard in Colorado.
"When that soil gets wet it can swell. And it swells at a tremendous force like 2,500 pounds per square inch. Most buildings really can't withstand that," USGS Colorado Director Vince Matthews said.
In Centennial, Barbara Stoker says she is dealing with the effects of swollen soil. The ground was so dry outside of her home, that it forced the floor in her living room to sink four inches.
"It felt like an earthquake," Stoker said. "The entire house shuttered. I had friends in from California. Some ran under the doorways; some ran outside."
The damage in her living room is most noticeable along the side of the walls and underneath the vents.
"When I called my insurance agent he said he never heard of a floor that fell four inches in his 30 years of working," Stoker said.
Swollen soil issues aren't covered by most insurance agencies.
(KUSA-TV © 2012 Multimedia Holdings Corporation)