Sinkholes can form anywhere there is soluble rock present underground. This is known as "karst terrain," according to Randall Orndorff, Director at the Eastern Geology and Paleoclimate Science Center of the United States Geological Survey. Soluble rocks that could potentially lead to sinkhole formation include limestone, gypsum and salt.
More than 20 percent of the country is above "karst terrain," which can produce a sinkhole, according to the U.S. Geological Survey (USGS).
Sinkholes occur most often in Florida, Texas, Alabama, Missouri, Tennessee, Kentucky and Pennsylvania.
Earlier this year, a 20-foot sinkhole in Florida swallowed a house and its resident after developing while the man was sleeping.
On Aug. 11, 2013, a 60-foot-wide sinkhole formed under the Summer Bay Resort in Clermont, Fla., prompting the evacuation of its guests. Nobody was injured.
Content contributed by Molly Cochran.
Expanding rainfall will bring good news and bad news for people in the northeastern United States into early next week.
Following an outbreak of severe thunderstorms at midweek, more storms will ignite over the southern Plains and will include the potential for flash flooding into the weekend.
Those looking forward to traveling or spending the bank holiday weekend outdoors across the United Kingdom will face bouts of rain and increasingly gusty winds.
Rain will threaten to put a damper on Walpurgis Night and May Day festivities across parts of Germany this weekend.
Enough cold air will be in place for another round of heavy snow to fall across Colorado, including Denver, to end the week.
One of the largest severe weather outbreak so far this year occurred this week as powerful winds, large hail and heavy rains pummeled the Plains and parts of the Ohio Valley over the course of several days.
Washington, DC (1874)
30 degrees -- latest freezing temperature on record.
New York City, NY (1874)
1/2" of snow - latest measurable snow on record.
Taylor, TX (1905)
2" of rain in 10 minutes; 2.3" in 15 minutes.