AVON PARK – She first noticed it in her backyard about four weeks ago: a small hole not more than a half-foot in diameter.
But each week when Joann Moore went to mow her backyard, she noticed the hole behind her house, 8 S. Lantana Ave., getting bigger.
By Thursday, that six-inch hole had turned into a two-foot deep depression about five feet long and three feet wide -- and it seems to continue to grow, said Moore.
Now, Moore and the residents surrounding her Forest Hills Estates home off Forest Hills Court are looking for answers to what exactly caused the hole and how it got there.
“It started out, it was just a little, regular-sized hole. Then, it just kept getting bigger and bigger,” said Moore, who lives with her husband, Reggie Moore and 10-year-old son, Derrick Cobb.
Sinkholes form when rainfall percolating through the soil absorbs carbon dioxide and reacts with decaying vegetation, creating a slightly acidic water. The water moves through spaces and crevices underground and dissolves limestone, creating a cavities and voids, according to Southwest Florida Water Management District.
As the limestone dissolves, pores and cracks grow bigger and carry more acidic water, forming sinkholes when the surface above collapses into the cavities or when surface material is carried down into the voids.
Adding to the residents’ concerns is a 20-foot Duke Energy power pole about 20 feet south of the hole. Standing around the area Thursday morning, Moore and neighbors Patti McCall, who lives at 29 Forest Hills Court, and next-door-neighbor Theresa Mazza, 31 Forest Hills Court, mulled over the possible source of the hole and what it might do next.
Standing at a chain-link fence bordering her backyard and the hole, she said she and her husband, Frank, noticed no grass or dirt along the hole’s ridge and grass growing down into the breach.
Mazza said she has lived in the neighborhood for eight years and had never seen any other holes in the area in that time. She said what she found the most curious is that there is no dirt or grass along the rim, which would be there had someone been digging up the area.
“I know when these houses were built, trash was just buried around here; it could be just trash sinking in,” she said. “I really want to know what it is; is it safe? We want to know what’s going on.”
Since the hole was noticed, Mazza said she has contacted the Highlands County Sheriff’s Office. Spokeswoman Nell Hays said deputies responded to the area Wednesday at 5:50 p.m, investigated the area and reported the hole, which was then 2.5-foot by 2.5-foot hole, as a “suspicious incident” and the case was turned over to the City of Avon Park.
Sterling Ivey, spokesman for Duke Energy, said Duke wasn’t aware of any problems Thursday, but that a supervisor out of Lake Wales would be sent to the location to check on the hole within a day.
“It’s (the hole) close enough for us to do an evaluation on it and see if there’s anything we need to do with our lines that may be in the area,” he said.
In the past 30 years, there has been only one major sinkhole in Highlands County; that happened in 1989 on Valerie Boulevard north of Sebring. There, a 20-foot deep sinkhole took down two houses, according to an Associated Press article.
In December 2010, a hole grew to 140 feet wide, had filled with 3 feet of water and was 10 feet deep, at a 10-acre nursery owned by Orpha Hernandez near U.S. 27 in Venus.
Clint Kromhout of the Florida Geological Survey in Tallahassee is currently doing a study on sinkhole vulnerability around Florida. He said they’re uncommon in Highlands County and a massive sinkhole would be extremely rare. Locally the limestone is deeper and covered by sediments from an ancient mountain range, reducing water erosion of the limestone that cause sinkholes.
Avon Park City Manager Julian Deleon agreed heavy rains could cause sand, soil and water to go into pipelines and cause a hole to form.
“We want to make sure our facilities are out there and residents are safe,” he said.
But despite the assurance of area officials that the hole is safe, local residents want to get out of their sinking feelings. They hope to get concrete answers on the mystery hole soon.
“It’s not funny is someone is trying to play games,” said Mazza. “There should be somebody we should be able to call and not get the run-around.”
After a check at the site Thursday afternoon, Kevin Kirkman and Josh Turner, Avon Park utilities’ service workers, said it looked to them like the hole was formed due to the ground dissolving around buried debris such as concrete chunks. Turner said the utility department will remove the safety cones from around the area and fill in the hole without digging up any of the debris.