Boulder firefighters extinguished a small grassfire near Six Mile Reservoir in Gunbarrel this afternoon.

Crews from Boulder Fire Rescue, the Boulder Rural Fire Department and the Wildland Fire Division responded to the small blaze, which was located between Spine Road and the Diagonal Highway, near an office building located at 6000 Spine Rd.

The fire was likely started by sparks from a passing train moving along the tracks in the area, according to Boulder Fire Lt. Jay Ruggeri.

The fire was put out in around five minutes. Ruggeri estimated it burned 1/8 of an acre.

"It's very dry this time of year. It's the first day of spring and it is our first fire," Ruggeri said.