A gravel truck smashed into the back of a school bus on a foggy stretch of highway in central Alberta Wednesday, killing a 17-year-old girl and seriously injuring a 14-year-old boy.

Jennifer Dawn Noble, a grade 12 student, died after being taken to hospital with unknown injuries. It was her last year of high school and she had just received a graduation dress.

The bus had stopped around 8 a.m. to pick up some students on Highway 53, near Rimbey, Alta. -- about 120 kilometres southwest of Edmonton.

A gravel truck hit an SUV behind the bus, sending the vehicle into a ditch, and then the truck slammed into the bus, RCMP Sgt. Patrick Webb told CTV Newsnet on Wednesday.

Officials said heavy fog on the highway may have been a significant factor in the crash.

"Visibility was reduced considerably," said Rimbey Fire Chief John Weisgerber.

A spokesperson for the company that owns the gravel truck said the driver was extremely distraught, and that he knew parents whose children were aboard the bus.

Larry Jacobs, the superintendent of the Wolf Creek School Division, said there were about 12 students on the bus. Some were treated on the scene and then released.

"Our bus was stopped at the railway crossing, as they always do, and it was rear-ended," Jacobs told The Canadian Press.

"We have about 12 students on the bus. They were taken to a farm house nearby."

CTV Edmonton reporter Adam Kuzina said the back of the bus was ripped apart by the sheer force of the SUV hitting the rear of the vehicle.

Reports suggest the injured 14-year-old boy became trapped underneath the truck.

Grade 7 student Desirae Schmalz said she was sitting four rows from the back when the truck hit the bus.

"All I could smell was smoke," she said. "The back of the bus was all torn off and people were missing. I just jumped off the bus. I was so scared."

Jacobs said the board has contacted all the parents and a team of counsellors are at all of the school sites ready to help with any questions or grief issues.

Noble was a student at Rimbey Junior/Senior High School. Her uncle told The Canadian Press that Noble -- an outgoing teen who loved animals and talked of becoming a veterinarian -- was sitting in the back of the bus when it was rear-ended.

"She was a super kid. She was awesome. She was planning on going to college, she was funny, she was outgoing -- it's hard to explain,'' Keith Kreil told CP. "She was just a good person all around."

"She was the only child in that family, very close to her mom and dad,'' Kreil said, adding that Noble and her mother took trips to Florida together every year.

With reports from CTV Edmonton and The Canadian Press