SISTERS, Ore. -

A Portland man was critically injured Monday evening when his speeding car left Highway 126 east of Sisters and struck three trees, said Deschutes County sheriff’s deputies as they sought witnesses to the crash.

Deputies were dispatched around 5:30 p.m. to the reported single-car crash on Highway 126 about 200 yards east of Buckhorn Lane, two miles east of Sisters, said Lt. Chad Davis.

The car, a blue 2000 Porsche Carrera driven by Grant Prentice, 58, had been seen heading west on the highway at a high rate of speed before the crash and narrowly missed a cyclist riding on the highway, Davis said.

When the car reached a 45 mph corner west of Camp Polk Road, it left the highway, crossed a cinder shoulder and continued off the road until it struck two pine trees, Davis said.

The car then struck a third pine tree on the driver’s side, breaking the tree into pieces before coming to rest facing south on the north side of the highway, the lieutenant said.

Prentice was flown by Life Flight helicopter to St. Charles-Bend with serious injuries, Davis said. He was listed in critical condition Tuesday afternoon.

Speed was a factor in the crash, Davis said, urging witnesses to contact the sheriff’s office at (541) 693-6911.

Oregon State Police and ODOT crews assisted at the crash scene, Davis said.