The sinkhole that consumed two vehicles, killing one person Sunday evening was an unexpected tragedy and it could be awhile before we know what caused it.
However, it’s a frightening event that might leave many wondering if it could happen again.
Eyewitness News went searching for answers to how sinkholes happen and how rare they are for our area. Dr. Yongli Gao is a professor with the geological sciences department at UTSA. He has studied sinkholes all over the world. Some even bigger than the one created Sunday, which is about 12 feet deep and the entire width of the road. Dr. Gao said it would be way too early to know how Sunday’s sinkhole formed.
“Really, it’s hard to tell at this point,” Dr. Gao said.
Dr. Gao said there could be many factors at play like the surface beneath the ground, activity around the area and even all the rain leading up to the massive collapse.
“There are a lot of naturally occurring sinkholes and then there are some we call human induced sinkholes,” Dr. Gao said.
The San Antonio Water System (SAWS) has been doing construction in the area that included putting in a new 96-inch sewage pipe. That project ended in October of 2015. SAWS is currently replacing an older pipe just north of the sink hole.
SAWS President and CEO Robert Puente said there may have been a burst where the old and new pipe meets, which is around the area where the sinkhole happened. However, it’s too early to tell if that was the cause.
“We don’t know how this happened. The pit is full of water, sewer water, so until that is dewatered and we have an opportunity to look inside, we’ll know what happened,” Puente said.
According to Dr. Gao, sink holes are nothing new to the area but are usually seen on the city’s north side closer to the Edwards Aquifer, which is why he’s surprised to see one so far south.
When asked if a sinkhole like the one seen Sunday could happen anywhere throughout San Antonio, Dr. Gao said, “Yeah it’s possible, but I would say the probability is pretty low.”
Dr. Gao said one major reason sinkholes are rare in the southern part of San Antonio is because the bed rock is usually pretty far down beneath the ground surface. Congressman Joaquin Castro issued a statement Monday saying the tragedy “emphasizes the vital importance of sound infrastructure.”