As of 11 p.m., emergency responders were in cell phone contact with the man, and had found his vehicle near the Tarbell picnic area off Forest road L1100.

The man told searchers he could see a spotter plane on the scene, and was trying to signal it with his camera flash unit. He also said his cell phone battery was fast fading.

None of the four are believed injured. But two daughters have been separated at least six hours from their father and his son.

The Volcano Rescue Team is leading the search effort, with Clark County Sheriff’s deputies also involved.

The man told authorities his last contact with the daughters was about 4:45 p.m. Sunday.

The girls had water and backpacks, but no flashlights and limited clothing for night temperatures, the man reported.

Hours after nightfall, search crews had scrambled to pinpoint the father’s whereabouts using cell phone “pings” and GPS coordinates.

The group had apparently traveled the Tarbell Trail beyond Hidden Falls, near Sturgeon Rock in hilly country close to the Skamania County line.

The area lies east of the Dole Valley, about 6 miles southeast of Moulton Falls County Park and 8 miles southeast of Yacolt.