How to tell if there could be one in your yard

After a Florida man was killed in February when a 20-foot-wide sinkhole opened under his bedroom, many people wondered, Could that happen to me?

Thousands of sinkholes appear in the US each year—but sinkhole deaths are very rare. Only two other people are known to have been killed by sinkholes in the past 40 years in the US. Both were in Florida, and both people were operating heavy well-drilling equipment at the time.

Serious injuries are rare, too, though minor injuries such as twisted ankles from small, overlooked holes do occur. In March, a man playing golf suffered a dislocated shoulder after he fell into an 18-foot-deep sinkhole on a golf course near Waterloo, Illinois.

While the risk to life is low, the risk to property can be considerable. What you need to know…

THE RISKS
Sinkholes typically form when a relatively soft underground rock or bedrock—usually limestone but sometimes salt or gypsum—is eroded by water over time. This usually causes a gradual “subsidence” in the ground above the eroding bedrock as a bowl-shaped depression slowly forms. The process is called cover subsidence, and it’s the likely result when a sinkhole forms in an area with sandy soil. The process can take many years.

Occasionally the ground above eroding limestone remains almost perfectly in place before suddenly giving way, resulting in a cover collapse sinkhole such as the fatal one in Florida. This is particularly likely when the sediment overlying bedrock consists mainly of clay.

Fortunately, even these sinkholes typically give way over a period of hours, not seconds, as the surface topples into the sinkhole below, providing enough time to get clear. When this happens beneath a home, there usually are signs of the problems—cracking in the concrete of the foundation or exterior walls, for example—before the floor falls away.

Florida is the sinkhole capital of the country because limestone is the predominant bedrock for most of the state. But other states have sinkhole potential, too. Limestone outcroppings can cause sinkholes in parts of Alabama, Kentucky, Missouri, Pennsylvania, Tennessee, Texas and elsewhere. “Evaporative rock” such as salt or gypsum is found under 35% to 40% of the country, according to the US Geological Survey, although much of this is at great depth, reducing the sinkhole potential. (Click here for a map of affected regions.)

Sinkholes can occur just about anywhere else, too, when a leaking underground water pipe erodes soil…or when wooden construction debris or tree stumps are buried beneath soil and slowly rot away…or when mining activity has occurred beneath the land.

Example: The collapse of a century-old mine caused a 30-foot-wide sinkhole under a Springfield, Missouri, neighborhood earlier this year, endangering two homes.

Sinkholes can happen at any time, but they’re more likely when the groundwater table or hydrostatic pressure changes rapidly, such as when there’s heavy rainfall after a dry spell or a new water well is put into service.

EARLY SIGNS
Watch for the warning signs that a sinkhole is developing underneath your home or elsewhere on your property.

Possible signs include windows and doors that suddenly become difficult to open…rapidly expanding foundation cracks that are wider than hairline cracks (wide cracks that form a “stair step” pattern are particularly common with sinkholes)…or cracks in a section of the basement floor. However, these symptoms might instead mean that the home is simply settling.

Early signs of a sinkhole under your lawn or landscaping could include water pooling where it previously didn’t after rains…or trees or fence posts that suddenly start to lean. However, leaning trees and fence posts could instead be caused by heavy rains or high winds, among other causes.

WHAT TO DO
If the sinkhole is less than a few feet across and less than a few feet deep and not under or immediately adjacent to your foundation (or your swimming pool or some other valuable structure), just fill it with sand or soil or have someone do this for you.

If you discover rotting wood or other organic debris in the hole, clear this out first. Compact the new soil, and watch for further subsidence before laying down new sod.
If the sinkhole continues to expand after you’ve filled it, consider pouring concrete into the hole. This sometimes can act as a plug with a small sinkhole, preventing further problems.

If the sinkhole is larger than a few feet across or deep, however, it’s best not to try to fill it yourself—it might not be safe to stand near the hole. Rope off the area using wood stakes and yellow or orange warning tape to prevent accidents, and call in water, septic or sinkhole professionals.

If the sinkhole is near underground water pipes, call the local water utility. If you see a depression where you know water or sewer pipes run, or if you can see a pipe in the depression, it is best to call. Leaking water eroding the soil could very well be the cause of the hole—leaking water is the most common cause of sinkholes outside Florida.

If the leak is coming from a municipally owned water pipe, the utility company should pay to fix the problem. If the sinkhole is in the vicinity of your septic tank, call in a septic system specialist to see if water from that is causing the issue.

If leaking water seems not to be the problem, then call in a professional geologist or engineer experienced with sinkholes. In Florida, these sinkhole-remediation professionals are common and well-advertised. In the rest of the country, you might have to contact a home inspector or real estate professional to ask if he/she can recommend someone.

It also is worth calling the professionals if the sinkhole is under or adjacent to your foundation. These pros can use tools such as ground-penetrating radar to find out what’s going on under the home and take steps to prevent further damage, such as injecting special grout into the ground to provide stability.

It’s usually not necessary or cost-efficient to call in an engineer, geologist or insurance agent for a small sinkhole that does not threaten a structure. The costs of these professionals can be steep.

Also, having a known sinkhole on your property could lower its resale value, even if the hole is filled and fixed—the word “sinkhole” is enough to scare off some buyers. And insurance is unlikely to cover the cost of fixing the problem (although policies sold in certain states do provide some sinkhole coverage).

Source: Gerald Black, a licensed professional geologist and vice president of environmental field operations for Geohazards, Inc., a geological investigation and consulting firm in Gainesville, Florida. http://www.Sinkholes.com

Since that dark day, the families of Newtown and their supporters have turned their sorrow into strength, their pain into perseverance, their unspeakable loss into unmatched courage and determination to carry on. They come as Americans who wish to spare their fellow parents and family members the mourning, fear, and terror they felt six months ago.

Their message is clear: honor the memories of their little children and their educators by helping ensure that no other family is forced to endure such an unimaginable tragedy. Now, our task is plain: we must restore confidence in the safety of our communities by taking clear, effective steps to prevent gun violence in our schools, homes, and neighborhoods. That is why I am calling for a vote on a bipartisan bill by my California colleague Congressman Mike Thompson, New York Republican Congressman Peter King, and 180 sponsors to expand and strengthen our system of background checks.

Six months ago, in Newtown, a lone gunman took the lives of 26 Americans. Since then, nearly 5,000 more Americans have fallen victim to gun violence. Now, in Congress, we must summon the courage to act. We must heed the moving words of the Sandy Hook promise: “Our hearts are broken; our spirit is not.”

Congresswoman Pelosi speaks on the House Floor to commemorate the six-month anniversary of the tragic shooting at Sandy Hook Elementary in Newtown, CT

Where are the jobs bills?
On Wednesday, the twenty-three House Republicans on the Judiciary Committee – all men – advanced a bill to restrict women’s health choices making no allowance for protecting the health of women, or the victims of rape and incest. The author of the bill, Congressman Trent Franks (R-AZ) went so far as to say “the incidence of rape resulting in pregnancy are very low.” The bill will be brought to the floor of the House for a full vote next week. But the American people are asking: “Where are the Jobs?”

In the six months since Congress has convened, the House has passed just thirteen bills—and none of them have had anything to do with jobs. Enough is enough. It’s time to appoint budget conferees so we can engage in an open debate on a budget that replaces the across the board cuts with a plan to create jobs, strengthen the middle class, and responsibly reduce the deficit.

#Dontdoublemyrate
Time is running out. With less than ten legislative days to act before a looming increase on student loan interest rates hits more than 7 million students and families, House Democrats sought to force a vote on key legislation that would stop the doubling of the interest rate on subsidized Stafford loans on July 1. The Student Loan Relief Act was introduced by Rep. Joe Courtney on April 17, 2013, and has over 150 cosponsors, but Republicans have failed to schedule a hearing on the bill.

Instead of acting swiftly to protect our nation’s students, House Republicans made matters worse by passing the Making College More Expensive Act, a student loan bill with even higher interest payments by students and families. According to the nonpartisan Congressional Research Service, under their bill, students who borrow the maximum amount of subsidized and unsubsidized Stafford loans over five years would pay nearly $2,000 more in interest costs than if interest rates doubled.

The Democratic bill continues to allow college students to benefit from historically low interest rates by freezing the current low 3.4% rate for the next two years – and Congress must act quickly as the clock ticks. With a majority of new jobs in the next decade requiring a college degree, it is an economic necessity that a higher education remains an opportunity for every student, not a perk for the privileged few.

Please feel free to forward this information to your family and friends. To learn more about these efforts, to express your views, or to sign up for email updates, please visit my website. I am also on Twitter at http://twitter.com/NancyPelosi.

best regards,