UPDATE: The missing small plane with a Seattle man and his brother on board has been located near Yellowstone National Park, say Wyoming officials. The condition of the occupants is still unknown.

Park County Sheriff's officials say the 1963 Mooney M20C aircraft was located at 9:19 a.m. on the eastern slope of Howell Mountain in a steep ravine with a large cornice of snow above it. Officials say the plane had heavy front end damage and one wing had been torn from the plane.

A helicopter was able to land two search and rescue personnel above the wreckage. Tests determined that the snowpack directly above the plane was unstable and the risk of avalanche was too high to try to reach the plane.

A Black Hawk helicopter is en route to Cody from the Air Force National Guard base in Cheyenne. Once it reaches the scene, personnel will examine the best option for rescuers to reach the plane.

This is a breaking news update. The following is the previously published story.

CODY, Wyo. - A search and rescue team is looking for a single-engine plane with two people on board that may have crashed near Yellowstone National Park.

Park County sheriff's officials say the 1963 Mooney M20C was last seen Tuesday departing Yellowstone Regional Airport in Cody. On board were 84-year-old Robert L. Zimmerman of Huntsville, Alabama, and 86-year-old Ward H. Zimmerman of Seattle, Washington.

The brothers were headed from Cody to Twin Falls, Idaho, and from there to Seattle.

Radar last detected the plane about seven miles outside the Yellowstone east entrance in northwest Wyoming. Poor weather prevented an aerial search but searchers were on the ground in that area Sunday.

The search began after police in Idaho on Saturday asked Park County officials to check for the plane at the Cody airport.