The bus veered into the median separating the two lanes of the highway in the predawn darkness and fell into a 50-foot (15-meter) ravine at about 5:30 a.m. CDT (1030 GMT), said Baldwin County Sheriff Hoss Mack.
For whatever reason, the charter bus got into the median and ended up going into a ravine,” Mack told reporters near the scene of the accident on Interstate 10 between Mobile, Alabama, and Pensacola, Florida. “We have one confirmed fatality.”
A spokeswoman for the Alabama Law Enforcement Agency said later that the bus’s driver died in the accident.
The injured passengers, including one listed in critical condition and five in serious condition, were taken by helicopter and ambulance to 10 hospitals in Alabama and Florida, Mack said.
The bus was carrying 40 students from Channelview High School in Texas and six adults, the Channelview School District said in a statement.
"We are now focused on getting everyone back safely to our community,” the statement said.
The bus was one of two carrying Channelview Falcon Band members and chaperones back to their community, about 20 miles (32 km) east of Houston, after a long weekend trip to Disney World in Orlando, Florida, said Marcus Kramer, a spokesman for the Channelview school district.
"They’re a very successful band,” said Kramer, adding that the second busload of students was due back at Channelview later on Tuesday.
The band’s Facebook page on Monday updated its cover photo with an image of its members posing at Disney World.
Dozens of people posted messages of grief and sympathy on the school’s Facebook page, saying they were praying for the students.
Officials said the accident’s cause would be investigated by the Alabama Law Enforcement Agency.
The National Transportation Safety Board said it was sending a team of six investigators to look into the crash.