Kelsey McLean was driving a Jeep Grand Cherokee westbound on Montana Highway 64 when she crossed the center line and hit a dump truck, said Trooper Bertie Lau, with the Montana Highway Patrol.

She was killed instantly, Lau said.

McLean was about a mile outside Big Sky, Montana, headed up a hill when it happened, Lau said.

It is unknown if McLean fell asleep behind the wheel or if alcohol was a factor in the crash, but the latter is not suspected, Lau said. The trooper also does not suspect that excessive speed played a role.

McLean’s identity was released Tuesday by Undersheriff Dan Springer with the Gallatin County Sheriff’s Office.

mshinn@ durangoherald.com

This story has been corrected to reflect that Trooper Bertie Lau did not say if Kelsey McLean fell asleep while driving.