The Summit County coroner's office says a retired Army Lieutenant Colonel died while skiing at Breckenridge.
Deputy coroner Mike Schmitt says 57-year-old Paul Nelson, of Lafayette, may have lost control while skiing before heading into trees.
The resort says the accident happened Wednesday as Nelson was skiing on the intermediate Claimjumper trail on Peak Eight.
A cause of death hasn't been determined.
Nelson's son-in-law, Michael Scanlon, says Nelson inspected Russian nuclear plants for compliance with treaties while stationed there during the 1990s.