An American Fork Marching Band instructor was killed and dozens of students injured Saturday evening when their bus crashed on their return trip from a competition at Idaho State University in Pocatello.

More than 50 students in the band's woodwind section and two adults were on the bus when the driver momentarily "blacked out" about 7:15 p.m. on a stretch of Interstate 15 about 50 miles north of the Utah-Idaho border, according to reports.

Parents and students said band instructor Heather Christensen grabbed the wheel, but the bus crashed and tipped onto its side. Christensen, 33, of Spanish Fork, died at the scene.

"Everyone looked over and started flipping out," said Andrew James, a band member who was riding in a bus just behind the crash.

James, a junior who plays bass drum in the band, credited the instructor for saving the lives of her students.

"Only about 8 feet from where the bus tipped, there was a huge ditch," he said. "More people would have died if it weren't for her."

Idaho state police said the driver had a medical condition, which led to the crash. One parent said the driver had complained of illness earlier in the day.

Two students were taken to hospitals by helicopter, though police said their injuries were not life threatening. Other students were taken to Portneuf West Medical Center with minor injuries.

"We're on a bus right now, taking about 30 kids back to the hospital in Pocatello with some minor injuries," band director John Miller told the Deseret News about 9 p.m.

Miller said he was traveling "a ways behind" the bus that crashed.

Three of the four buses in the caravan were returning to American Fork late Saturday. Meanwhile, some parents were making their way to Idaho.

Michelle Hyde, who has two sons in the band, said the students were in shock Saturday as they began dealing with the death of their instructor.

"I don't know if they've had a chance to process it," an emotional Hyde said. "My kids are teary eyed, but they're boys. They're stoic."

"Right now everyone seems to be OK," said James, who was on a bus headed to Brigham City and then American Fork late Saturday. "I'm not too depressed. I'm really shocked. I'm so sad, of course, it happened."

James said the instructor who died was beloved by her students.

"She was a great instructor," he said. "Really nice to everyone. I loved her."

Mike Huestis, assistant band director, was on the road back to Utah when he received a text message telling him about the crash.

"Now we have to think about the future," he said. "Our next competition will be at BYU on Tuesday. Knowing (the instructor), she'd definitely want us to perform," he said.