AN ANTONIO -- Up to five homes are in danger of collapsing after a massive shift in soil that led to the evacuation of 20 homes in the Rivermist subdivision on Sunday. Residents say they heard and saw a 40-foot retention wall cracking in the days leading up to the sinkhole. The cracks started small Saturday morning but grew larger by the hour and once the ground started to slide, 20 homes above and below the wall were evacuated. Centex is the developer and their engineers were on the scene Saturday and are expected to stay there in the coming days to evaluate what is going on beneath the soil and how homes may be saved. “I wouldn't be surprised to wake up Monday morning to see these homes broken and falling down the hill.” said District Fire Chief and Emergency Management Coordinator Nim Kidd who also estimated the ground is moving approximately 4 inches per hour. A Centex spokesperson answered questions from residents at O’Conner High School late Sunday and assured them they are working to assess the problem and accommodate the displaced families. However, residents also learned they will not be allowed back to their homes while the ground is still moving. While many were upset they would not be able to grab important work clothes and other items, emergency management says it would be a mistake to let everyone grab their belongings on such unstable ground. Instead, only necessities such as medication will be retrieved by EMS workers. Several rooms were booked at the Drury Inn at 1604 and I-10 for residents, and the Red Cross is also assisting. An update on the situation and what lies ahead for residents will be given at the Drury Inn at 6 p.m. Monday. One homeowner told KENS 5 that the incident isn't the first with Centex. "We've been having problems with Centex," Javiera Arana said. "My wall had problems with cracks. They come and pack it with cement... [That's] all they do."