OSCEOLA, Wis. — A 13-year-old girl who was participating in a snowmobile safety class died after her machine suddenly accelerated, veered off a training course and crashed into a loading dock in western Wisconsin.

The Wisconsin Department of Natural Resources identified the child Monday as Sarah Thorsland of Osceola.

The girl was negotiating a pattern of traffic cones outside Osceola High School in Polk County on Saturday when the snowmobile accelerated and hit the loading dock, police said.

The girl’s mother, a nurse, ran to join first responders in life-saving efforts. The girl was airlifted to Regions Hospital in St. Paul, Minn., and then transferred to neighboring Gillette Children’s Hospital, where she arrived in critical condition. Authorities said the girl died at that hospital on Sunday.

It’s unclear why the snowmobile accelerated when Thorsland was at the controls. About 42 participants were using the snowmobile, outfitted with wheels on the skis, to take turns on the slow-speed maneuver course.

The DNR-sanctioned class was taught by volunteers from the local snowmobile club, and the instructor had been teaching the class for 31 years and had never had any incidents, Osceola Police Chief Tim Lauridsen said.

DNR officials said they believe Thorsland’s death is the first fatality to occur during any DNR safety class. The crash remains under investigation.

“Safety is our highest priority,” DNR Warden Todd Schaller, chief of the agency’s Law Enforcement Bureau’s Recreation Education and Enforcement Section, said in a statement. “We do not take Saturday’s tragic loss of Sarah lightly in any way.”