Troy Green, 39, of San Antonio went to Colorado for a conference, but his wife contacted Denver police after he didn't get in touch with her Thursday, The Denver Post reported.
Dozens of ground searchers aided by rescue dogs and aircraft hunted for Green in the vicinity of the park where other visitors believe they saw him Thursday afternoon.
A car matching the description of Green's rental car was found Friday morning in the the park's Bear Lake parking lot, park rangers said.
Park spokeswoman Kyle Patterson said it had been determined Green purchased hiking gear after arriving in Colorado, the newspaper said.
"It is possible that he was wearing black snow pants, a black puffy down jacket, black gloves and a black balaclava," she said, in an email Sunday. "He also was seen wearing hiking boots and a royal blue and gray camelback."
Nine inches of snow fell in the area between Wednesday and Friday.
"Searchers continue to face winter conditions with deep snow, winds and drifting snow," Patterson said.