Randy Udall, brother of Colorado's U.S. Senator Mark Udall, missing on hike in Wyoming

WYOMING - Sen. Mark Udall's brother,  James "Randy" Udall, is missing in the backcountry of the Wind River Mountains of western Wyoming, near the town of Pinedale.

According to the Sublette County Sheriff's Office, Randy Udall was already two days overdue when he was reported missing on Friday.

Search operations began on Friday afternoon and continued over the weekend with assistance from the U.S. Forest Service. The search area is approximately 225 square miles.

The searches have involved four search and rescue teams on the ground and  two helicopters -- one from the National Guard and one contracted to the Sublette County Sheriff's Office.

The search was suspended overnight because of darkness, but authorities said it will resume Tuesday morning.

"Mark is concerned about his brother’s whereabouts and he continues to closely monitor the situation. He and his family hope for the best," Senator Mark Udall's Press Secretary, James Owens, said.

The sheriff's office said the 61-year-old Carbondale, Colo., resident is an experienced backpacker who has hiked in the Wind River Mountains many times over the past 30 years. 

"All the information we have is he had the supplies to be able to do his trip. As far as emergency beacons, we're not aware of any," said Sheriff Dave Lankford.

 "This is a large scale search over a large area. We're working on elevations from 8,500 feet to 13,000," the sheriff said. Fortunately, Lankford said, the weather has been good lately with overnight temperatures near 50 degrees.

He left Elkhart Park trailhead in the central part of the Wind River Range on June 20 and was scheduled to exit the mountains on June 26. The environmentalist was hiking alone.

He is described as 6 feet 4 inches tall, 200 pounds with gray/brown hair and blue eyes. If you have been in the Wyoming backcountry recently and have seen a man matching this description, contact the Sublette County Sheriff’s Office at (307)367-4378.