Search crews were unsuccessful Sunday in finding a man missing in Rocky Mountain National Park, according to a park news release.

Steve Grunwald, 24, of Greenville, N.Y., was reported missing by a friend on Thursday after not contacting his friends or family since Aug. 28.

National park rangers found Grunwald’s car parked at the Glacier Gorge Trailhead Thursday.

On Sunday, searchers covered terrain along the Continental Divide including areas of Thatchtop, McHenrys Peak, and Powell Peak.

Another search team hiked from the Glacier Gorge Trailhead to the South Couloir route up Thatchtop.

Aerial search efforts took place Sunday as well.

Searchers were camping Sunday night in the Lake Powell area to begin search efforts again early Monday morning.

Grunwald’s route and destination are unknown, but it is believed he may have been attempting the Glacier Gorge Traverse on Aug. 29. The Glacier Gorge Traverse includes 11 peak summits over roughly 19 miles, entailing sections of fifth-class climbing and difficult terrain. 

Grunwald is described as 5 feet, 6 inches tall, 145 pounds with brown, medium-length curly hair. He wears black rectangular glasses and is described as a fit trail runner, backpacker and climber.

His clothing may include a brown beanie, yellow pants, a blue top layer and blue or red shoes. He may be wearing a green Camp climbing helmet.

Grunwald was last seen in Boulder on Aug. 28.

RMNP said investigative leads from the tip line have been positive and continue to assist in defining the search area.

Anyone with information about Grunwald, or who was in the upper Glacier Gorge area or surrounding peaks on Aug. 29 or Aug. 30, is asked to contact the RMNP at (888) 653-0009 or online at www.nps.gov/ISB.