Two Bend residents were flown to a Bend hospital with injuries and two young children received minor injuries late Monday night when their SUV left U.S. Highway 20 west of Sisters, struck a tree and overturned, Deschutes County sheriff’s deputies said.

Deputies responded around 11:30 p.m. to Highway 20 near Cold Springs Road on the reported crash, said sheriff’s Sgt. Kevin Dizney.

They arrived to find a red 1992 Ford Explorer on its top on the eastbound shoulder, partially blocking the eastbound lane, Dizney said.

The car, driven by Hanna Brant, 22, had drifted off the road and struck a tree, causing substantial front-end damage,

All four occupants were out of the SUV when deputies arrived. Sisters-Camp Sherman and Black Butte Ranch fire medics provided assistance as two air ambulance helicopters were dispatched to help due to possibly life-threatening injuries.

Brant and passenger Chastitie Wahl, 26, were flown to St. Charles Bend, where Wahl was treated and released while Brant was listed in serious condition Tuesday evening, hospital officials said.

Dizney said an initial investigation did not determine why the driver had drifted off the road, but he said alcohol and drugs were not believed to be factors in the crash. It appears all four occupants were wearing seat belts or in child seats, he added.

Black Butte Police, Oregon State Police and ODOT also assisted at the crash scene, Dizney said. The highway was closed for about a half-hour in both directions to allow a possible landing zone for the helicopters.