More search and rescue teams will be looking for a father and son from Minnesota missing near Mount Evans west of Denver.
The search Tuesday will include about 50 people.
Authorities say 51-year-old Damian McManus and 19-year-old Evan McManus, who are from St. Louis Park, Minn., were last heard from on Wednesday.
Alpine Rescue Team spokesman Bill Barwick says searchers are not sure the father and son were equipped for wintry conditions in the Rocky Mountains.
Barwick says the two men left for a camping trip on Wednesday and were due back on Sunday. They had driven to Colorado from Minnesota and planned to stop and hike along the way as part of their father-son trip for spring break.