Updated

Two small planes collided near an Oregon state park Tuesday, sending one crashing to the ground and spreading debris across a wide area, authorities said.

The second airplane managed to make an emergency landing in Champoeg State Park, about 25 miles south of Portland, and the two people inside walked away, police said. Authorities didn't know how many people were on board the plane that crashed and disintegrated.

The planes collided at about 4 p.m. over farm country along the Willamette River. There are a number of small airports in the area.

Capt. Ken Summers of the Yamhill County sheriff's office said one of the planes crashed into trees and exploded on impact.

Jack Crabtree, the county sheriff, told The Oregonian that plane apparently broke up in mid-air. He said part of the fuselage landed south of the Willamette River and another part landed north of the river.

Debris from the demolished plane was scattered around Champoeg State Park, including upholstery and pieces of a wing, Oregon State Police Senior Trooper Douglas Brown told The Associated Press.

The Oregonian quoted a resident of the area as saying the impact was so great that he thought it was an earthquake.

"The whole house shook, the dishes rattled, and I thought it was the big one," Robert Nelson told the newspaper.

Witnesses said they saw a huge column of black smoke after the impact, KGW-TV reported.

The location of the crash indicates the planes weren't on a commercial or private charter flight pattern, Federal Aviation Administration spokesman Mike Fergus said.