In 1986, Udall and his wife went on a group trek of Mount Garmo. During the climb, Maggie broke her leg, and their fellow climber, Steve Monfredo, died on the mountainside. Udall's 61-year-old brother, Randy Udall, went missing on June 26, 2013, after going on a solo hike in Wyoming's Wind River Range. On July 3, 2013 a body, later identified as that of Randy Udall, was found approximately 80 miles southeast of Grand Teton National Park.