Authorities said numerous students were transported via helicopter to emergency rooms.
The tour bus, which was transporting a high-school band, crashed off the Interstate 10 expressway into a 60ft ravine, injuring between 12 and 20 people, according to a statement from the Sheriff's Office.
Mark Kramer, public relations officer with the Channelview Independent School District, said the bus was taking Channelview High School band students back to Houston after a band trip to Disney World.
Several hospitals were placed on alert for the injured.
Officials from the Baldwin County Sheriff's Department and Mobile Fire and Rescue said the ravine is estimated to be between 50 to 60 feet deep. We're told five of the passengers were in serious condition and one in critical condition.
The sheriff said it wasn't immediately clear what caused the bus to enter the grassy median, which abruptly ends at a steep embankment where the interstate passes over Cowpen Creek. Rescuers had to repel down into the ravine to reach the bus, and some passengers were evacuated using ropes, Mack said. He said at least one person had to be cut out of the wreckage.More news: Dota 2 gets subscription service Dota Plus
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Sacred Heart Hospital in Pensacola confirmed on its website that it had received 18 patients from the bus wreck on Tuesday. He could not provide information about the extent of their injuries or conditions.
About 45 people were on board, and all of them were brought to 10 hospitals in Alabama and Florida, either by helicopter or ambulance, he said.
Lowery said uninjured passengers will be reunited with family members and Channelview school officials at Coastal Church on County Road 64 in Daphne, Alabama.
A hotline was set up for Texas family members to call for a status update: 251-972-6807.
A second bus on the spring break trip, driving ahead of the one that crashed, is continuing on to Texas, the sheriff said.
According to Loxley Police, I-10 eastbound is shut down because a tour bus has fallen off a ravine.