Routt County Helicopters and planes could be seen and heard throughout the day in Steamboat Springs on Monday, during day two of a search for a downed aircraft carrying a Routt County man and his son.
But the search for the twin-engine Cessna 310 had been unsuccessful as of Monday evening.
The Civil Air Patrol on Monday expanded its search area to encompass 4,000 square miles in 11 counties, but because of bad weather, the seven planes and two helicopters involved in the search focused on Routt and Grand counties.
CAP incident commander Mark Young said the search will resume today and could continue through the weekend.
"It would be fairly easy for them to survive 10 days in the mountains," said Young, adding that the men had survival equipment with them on the plane. "We're going to try everything we can to find them."
The pilot and passenger of a plane that has been missing since Sunday morning were identified Monday as Levi Klapperich, 26, of Durango, and his father, Mark Klapperich, 56, of Hayden.
Riley Polumbus, spokeswoman for Routt County Search and Rescue, which assisted in the search locally, said Levi Klapperich has logged 3,100 hours of flying time.
"He's an experienced pilot for sure," Polumbus said.
The two men left Yampa Valley Regional Airport shortly after 8 a.m. Sunday, headed for Fort Collins. Levi Klapperich flew from Durango and picked up his father in Hayden, but the pair and their plane never made it to the Front Range.
Civil Air Patrol began a search at about 11 a.m. Sunday and called for help from ground crews at about 3 p.m., when Routt County Search and Rescue initiated its search north of Hayden, near California Park. Ground and air crews searched for several hours before the ground crews relocated to Rabbit Ears Pass.
The ground search on Rabbit Ears Pass resumed at about 9 a.m. Monday. Polumbus said two snowmobile search crews were sent to search areas north and south of Dumont Lake. They found nothing by the time the ground search ended at 6 p.m.
Searchers were particularly interested in the Morrison Creek and Harrison Creek area. Polumbus said Search and Rescue members can recall three aircraft that have crashed there before.
Polumbus and Young said searchers still have been unable to pick up any transponder signals from the aircraft. Commercial, private and search planes have been listening for the signal.
"It is a bit concerning, but we have no idea what to make of that yet," Polumbus said.
Tracking an aircraft from departure to arrival by radar is not possible at certain elevations and locations in the Colorado mountains. Young said CAP has identified three broken radar tracks of interest, and any one of the three might belong to the missing plane.
"We've researched all three and so far haven't found anything," Young said.
Two of the radar tracks ended in the California Park and Rabbit Ears Pass areas in Routt County, which have been searched extensively by air and ground.
The third broken radar track goes over Mary Jane at the Winter Park ski area.
"We're going to keep searching all three of those areas tomorrow," Young said. "At this point we haven't ruled out anything."
Young said CAP had requested air assistance from the military, but the military was not able to help because of bad weather. That decision will be reevaluated today, Young said.
Friends of the missing men have also been searching the county on their own, Polumbus said. Search and Rescue will not be sending up a search helicopter Tuesday like they did Monday, but a ground crew might search the Harrison Creek area on Rabbit Ears Pass.
Polumbus said Search and Rescue members were talking to Mark and Levi Klapperich's family throughout the day Monday at the Search and Rescue Barn on Yampa Street.
"They're hanging in there," Polumbus said.