West Vancouver Police are asking the public for help finding two men lost on a North Shore mountain after setting out for a day trip on Christmas Day.

Officers were contacted late Sunday night when a car was found by staff in a Cypress Mountain parking lot after closing hours.

An investigation was launched to find the registered owner of the vehicle, 43-year-old Roy Tin Hou Lee of Vancouver.

Police say Lee is "an avid hiker" who set out to snowshoe on Christmas Day with 64-year-old Chun Sek Lam, also of Vancouver. Both men are experienced, but not prepared for overnight conditions.

North Shore Rescue is helping police with the investigation, and a helicopter was sent up before dawn. The air search was largely grounded due to snow during the day.

Twenty search and rescue members were on the trails for much of Monday searching for the missing men, but they had not been spotted by sunset.

Fresh snow is making the search more challenging, crews say, and avalanche risk is being monitored.

"The weather is obviously getting worse," said search manager Simon Jackson. "Right now without further navigation we don't have anything to narrow our search down."

Temperatures were expected to drop to -11 overnight, and more snow was predicted.

Anyone with information is asked to contact West Vancouver Police at 604-925-7300.

With files from CTV Vancouver's Tom Popyk