The Coast Guard is investigating the cause of a parasailing accident that occurred last week in Panama City Beach, Fla.

Coast Guard Sector Mobile, Ala., and the Florida Fish and Wildlife Conservation Commission are conducting the investigation.

On July 1, two 17-year-old girls, friends from Indiana vacationing with their families, were seriously injured when the tow line parted from their parasail and they collided with the top railing on the roof of a high-rise condo before tumbling over the side, hitting a power line and landing in a parking lot.

Just a few minutes into their ride high over the water, “that’s when the cable had snapped and I’d seen them going away. I was just in complete shock during all of that,” Collin Good, brother of Sidney Good, told the Florida media.

Sidney and her friend, Alexis Fairchild, suffered head injuries. Sidney had a severe neck injury. The families say Alexis is now speaking, and walking farther and more frequently.

Sidney is on a ventilator and unable to speak, but she is able to communicate through sign language. She is scheduled to have neck surgery next week.

Click here for the full report with video of the accident by WJHG News.

The Indiana press is also covering the accident and investigation and INC Now reported that the teens are showing signs of improvement despite the traumatic injuries.

“Alexis is stable and able to talk with visitors and is working with therapy to slowly begin walking further and more frequently. While she is still in pain from her injuries, each day she is improving,” reads a July 5 statement from the families. “Sidney is also showing improvement and seems more alert today. She is still on a ventilator, so she is not able to talk, but has actually used some sign language to communicate with her mother, even asking for a scratch on her cheek. Sidney is still critical and is expected to have surgery to stabilize her neck early next week.”

Click here for that full report.