The brother of Sen. Mark Udall (D-Colorado) has been missing for nearly a week after taking a hiking trip in Wyoming.

Randy Udall, 61, left for a solo hike along Wyoming's Wind River Range, a trail the experienced backpacker has reportedly hiked many times before, over a week ago. Two days after he was expected to return, authorities in Sublette County were notified of his absence.

"He is missing," Sublette County Sheriff's spokesman Steve Smith told the Denver Post. "He was supposed to be back on the 26th. We were notified on the 28th."

Rescue workers from a private company used ground teams and two helicopters to search over 225 square miles on Friday to no avail. The U.S. Forest Service continued the search over the weekend.

"Mark is concerned about his brother's whereabouts, and he continues to closely monitor the situation," Udall's office said in a statement. "He and his family hope for the best. (Sen. Udall) has remained in contact with those searching for his brother and, along with his family, has waited and hoped for the best.”

[via The Atlantic Wire]