Authorities say a passing driver who stopped to investigate a damaged tree in southwest Washington found two young Oregon girls injured in a car crash that killed their mother.

The Washington State Patrol estimates the car driven by 26-year-old Jessica Marie Rath of Astoria, Ore., hit the tree sometime early Wednesday morning.

The crashed vehicle wasn't visible from State Highway 401 south of Naselle.

Trooper Russ Winger said it's likely the 4-year-old girl pulled her more seriously injured 2-year-old sister from the car and covered both of them with a blanket. The overnight temperature was in the low 40s.

The girls were taken first to an Astoria hospital, where their father met them. Winger says the 2-year-old was airlifted to a Portland hospital.

The trooper says the mother had driven Tuesday night to the Hoquiam, Wash., area to pick up her fisherman husband but then headed south when she found out her husband's boat was headed elsewhere.