ORCHARD, Colo. -- A farmer trying to control a grass fire on his property died Wednesday afternoon when the tractor he was driving flipped into an irrigation ditch and crushed him.

Morgan County Sheriff Jim Crone said Charles Wynne, 55, was driving his tractor on top of a ditch to get ahead of the fire and cut a fire break, when the ground shifted or partially collapsed, causing the tractor to flip and roll on top of the farmer.

Wynne was killed instantly.

Wynne was plowing his ground when the fire started. He called for the fire department at about 2:45 p.m, alerting them that a grass fire had jumped a ditch and was out of control. Investigators don't know if Wynne was burning or if the ditch company was burning in the area.

"As the tractor got to the ditch, it drove onto the access road that runs along the south side of the ditch. As the tractor turned right on to the road, the left wheels got too close to the edge of the ditch and the bank gave way," Crone said.

Wiggins, Fort Morgan and Platte Valley fire departments all responded to the scene.

One of the first Wiggins firefighters arriving at the scene saw Wynne going through the smoke on his tractor. It wasn't until an hour later when another firefighter near that area discovered a tractor overturned in the Riverside ditch with a man pinned underneath.

The sheriff's office will continue investigating the cause and origin of the fire since there was a fatality involved.

About 100 acres were burned by the brush fire, located northwest of the town of Orchard, Colo. The fire is north of County Road Y, just east of the county line, along the Riverside Irrigation ditch.