Graham Lockwood was reported missing on Friday night.
The 44-year-old from Huddersfield has links to Wakefield but may have travelled to Scotland.
Graham is described as white with short, brown hair and of slim build. He is 5ft 10ins tall and could be wearing a jacket similar to the one pictured.
West Yorkshire Police said on Saturday that Graham, a former volunteer with Mountain Rescue, has links with the Bute, Fort William, Inverness and Loch Ness areas of Scotland.
It is possible Graham has travelled to the Great Glen Way that runs from Fort William to Inverness, or around the General Ward's Military Way along the eastern side of Loch Ness.
Anyone who knows of Graham's whereabouts or who sees him - including walkers - is asked to call West Yorkshire Police on 101, quoting log 1941 of Friday 13 December.